Digital BW, The Print

Martin,

So when does a Black&White print become a color print?

Bob Frost.

----- Original Message -----
From: "Martin Wesley" <mwesley250@...>

> This is at the heart of the issue with grayscale inks. One of the things
> that makes a toned silver print so wonderful is that it is not just shades
> of gray but that it varies in hue as it varies in luminance. That is why I
> am so fond of the MIS-VM and Selenium PiezoTone inks. They give you a
> variation in color as they change in density. This is important because it
> makes it easier for our eye to distinguish between different print
> densities. Our eyes seem to be incredibly sensitive to slight color
changes

> near the neutral point which makes it difficult to get a truly neutral
> print. What we want to do is to take advantage of that fact to enhance our
> prints.

----- Original Message -----

From: "royvharrington" <roy@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, August 04, 2002 8:45 AM
Subject: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> The tradeoff of gray levels versus resolution is really the entire
> basis of what's going on in printing.  Previously in this discussion
> there was distinction of pixels versus dots, but I think this is
> an unnecessary and misleading distinction.  Everything we have as
> far as Epson printers these days are pixels. The very smallest point
> on a print can contain any of 4 or 6 different gray/black inks drops,
> plus with variable droplet size and overprint of multiple drops,
> there are many possible gray values.  So I would call this a
> pixel not a dot.  The printer 1440 and 2880 dpi specs relate
> to high resolution, a few grays pixels.  Through the dithering
> process we tradeoff those high resolution pixels to get pixels
> with lower resolution but more gray values.

Pixels as used in image files have their bit value bound to the pixel
itself.
Representations on monitor screens in dithering do not affect the image file
properties on that aspect.
What is shown on your screen in dithering could better be described as false
pixels.

The dot formed by one droplet of the inkjet has to be compared with the
image setter laser dot or line that builds the screen/raster dot on an
offset plate (filmless systems), the screendot is one form of a cell.
Growing from 1 laser dot to 256 laserdots it is the most defined form of a
grey value cell. Yet that rasterdot can have shapes like round, square,
oval, chain, line. The same laserdot can build cells in a stochastic
pattern, the frequency of the laserdots per area represents the gray value.
This is more a cloud than a shape. Those cells can even overlap one another
to some degree. Laserdots sometimes have similar variable sizes as inkjet
droplets have. This is used as well in the creation of cells.

The term 'weaving' for inkjet cell formation is a vague definition with a
reason. The process is complex with all kinds of methods to represent grey
values and one extra goal: get rid of the defined shapes of pixels or
screendots. Ink densities, droplet sizes, dithering, stochastic patterns,
inklayer variations are all combined to get that result. Cells overlap as
well. Printing is build up in 4 successive strokes that allows an increase
in complexity and avoids ink bleeding at the same time. It can be done in
inkjet printing, there's no way this can be done in a conventional printing
process. In all that complexity sharpness and contrast must not be lost. It
isn't.

The translation of pixels through printer resolution, dot size, dithering,
ink densities to cells that represent grey values can be done in so many
ways that the cell is a very amorf entity. In coIour printing this is even
more complex.
I wouldn't use the term pixel for a cell like that. A pixel is far more
defined except in its size.

Add to that the usual pixel data in additive RGB and the unavoidable
subtractive printing in CMY(K).

Ernst

----- Original Message -----

From: "tboleyyh" <tyler@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, August 04, 2002 5:42 AM
Subject: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> --- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin"
<darkroom@i...> wrote:
> > Tyler,
> >
> > Before responding to your post, I have one simple question for you.
> >
> > If the file only contains 256 levels of gray, and IF (BIG IF) what you
claim
> > is true, that standard Piezo is capable of 1000 tones, where do the
extra
> > 744 levels of gray come from?  How, exactly, are they derived?
>
> Austin, I honestly can't explain it any better than I did. I really think
you have to think beyond your file, and see the entire
> system including the ink and paper.
> How about this to think about?
> 256 level grayscale file not altered in any way. Printed with a
hypothetical two ink printer.
> Exact same information sent to two mono inks of different density. Is the
tonal scale extended beyond the same thing
> printed with one ink?
> With respect Austin, I think I'm done with this. I also think, with
specific regard to the Piezography driver, someone from
> ConeTech would be far more qualified than I to discuss that system.
> If my previous BS didn't communicate properly that's my shortcoming. If it
did, but is flawed, I'd be interested in hearing
> how.
> Tyler

I was intrigued by a message from Jon Cone several months before Piezography
appeared. He seemed quite certain that the Epson 9000 was capable of droplet
size variations that were not used by the Epson driver but he wasn't certain
how it could be used. That is how I remember the content. Whether he
actually uses that kind of
extra capabilities of the Epson printers I don't know.

It doesn't make a difference on the 8 bit in 8 bit out discussion though.

Krawitz mentions something about the computing in the Gimp print driver;
that to get a better rounding off this is done in 16 bit where the end
result is then brought back to 8 bit figures (something like that). Maybe
Cone just doesn't round off but uses this routine till the end. I don't
think it brings more than a marketing advantage. A 16 bit image could be
handled even higher. Maybe it all is ridiculous because the Epson firmware
in the printer is so limited that no fancy calculations will ever get to the
printhead. There has to be a DA conversion before the heads. If it is
digital till the end then things are different. Frequency can be exploited
when the firmware allows it.

Ernst

Bob,

Good question but no clear cut answer. Probably depends upon the individual
perception of what is neutral and what is pleasing. I guess our best mono
color prints are not so mono after all. Before I started with all this
digital printing I had never looked so closely at my silver prints as I have
in the last year.

Martin Wesley

http://www.borderless-photos.de/guests.html

----- Original Message -----
From: "Bob Frost" <bobfrost@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Saturday, August 03, 2002 12:46 PM
Subject: Re: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> Martin,
>
> So when does a Black&White print become a color print?
>
> Bob Frost.
>
> ----- Original Message -----
> From: "Martin Wesley" <mwesley250@...>
>
> > This is at the heart of the issue with grayscale inks. One of the things
> > that makes a toned silver print so wonderful is that it is not just
shades
> > of gray but that it varies in hue as it varies in luminance. That is why
I
> > am so fond of the MIS-VM and Selenium PiezoTone inks. They give you a
> > variation in color as they change in density. This is important because
it
> > makes it easier for our eye to distinguish between different print
> > densities. Our eyes seem to be incredibly sensitive to slight color
> changes
> > near the neutral point which makes it difficult to get a truly neutral
> > print. What we want to do is to take advantage of that fact to enhance
our
> > prints.

----- Original Message -----

From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Saturday, August 03, 2002 8:15 PM
Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> Tyler,
>
> Before responding to your post, I have one simple question for you.
>
> If the file only contains 256 levels of gray, and IF (BIG IF) what you
claim
> is true, that standard Piezo is capable of 1000 tones, where do the extra
> 744 levels of gray come from?  How, exactly, are they derived?
>

Austin,

If the same 256 levels of gray pixels are fed to the printer and it has four
channels each with a different shade of gray ink, it would seem to follow
that each channel will print those 256 levels differently resulting in
overall tonal interpolation. Lower than 1024 but greater than 256.

Assume you didn't partition the inks at all. Then each channel would try to
print the entire range of 256 levels. One would have a Dmax of 100% and the
others say 75%, 50% and 25%. As these four channels are printed together
wouldn't this produce intermediate levels between the 256 input levels? In
practice the inks are partitioned so that each covers a specified segment of
the 256 levels input to the driver but the crossover points overlap a great
deal with multiple inks being applied in the same tonal range. The only way
to I can see to get a precise 256 levels would perhaps be to use a single
ink.

I think the analogy to the pixel discussion is very apt. While we input
pixel information to the printer is does not print pixels. The same with
levels of gray. We may input levels but the driver and the nature of the
inks produces an interpretation of those levels in a manner designed to
convince our eyes that they are observing a continuous tone image.

Martin

--- In DigitalBlackandWhiteThePrint@y..., "Martin Wesley" <
mwesley250@e...> wrote:
> ----- Original Message -----
> From: "Austin Franklin" <darkroom@i...>
> To: <DigitalBlackandWhiteThePrint@y...>
> Sent: Saturday, August 03, 2002 8:15 PM
> Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?
> 
> 
> > Tyler,
> >
> > Before responding to your post, I have one simple question for you.
> >
> > If the file only contains 256 levels of gray, and IF (BIG IF) what you
> claim
> > is true, that standard Piezo is capable of 1000 tones, where do the extra
> > 744 levels of gray come from?  How, exactly, are they derived?
> >

Hi Austin,

Sorry for joining late, but I've been away.
Your arguments seem so self-evident that it hard to see what else is
going on.  Say you were to create a 8 bit grayscale file with 256
separate one inch squares such that each square contained a different
gray value -- i.e. 0,1,2,... 255.  Each square has a different
gray value and at least theoretically a different gray tone on the
print --> thus there are 256 gray tones possible.  This is your
argument, right?

This isn't the whole situation though.  Say there are two adjacent
gray tones, values 102 and 103.  Let's make a new square that is a
checkerboard of thes two values.  What gray tone does this produce?
What are the possibilities:  first is that the pixels are big
enough that we see the checkboard pattern, however if the resolution
is high enough or our detector resolution gets lower, the two gray
values 102 and 103 merge together and average to 102.5.  This is
a new and additional gray tone.  You could do this between each
original pair.  Also you could do 75% 102's and 25% 103's giving
102.25.   You can also change the pattern to be more random making
it even more likely to be undetected.  This is dithering at the
pixel level.  Photoshop does this for gradients.  If you create
a gradient from 0 to 255, how many tones of gray depends heavily
on what resolution you look at it.  Same thing with the printer,
how many grays depends heavily on how close (resolution) you look.
In fact in the halftone printing they have this simple formula:

Gray levels = (output resolution/screen freq)^2 + 1

   where output resolution = the image setter dpi
   and screen freq = lines per inch  or
          pixel resolution on output.

With dithering or stochastic screening there is no fixed resolution
but the general idea still holds.  There is always a tradeoff
of more gray levels versus more resolution.  (this is one reason I
strongly object to the notion of counting the number of grays in
a print -- it depends on how you look not just the print).

The tradeoff of gray levels versus resolution is really the entire
basis of what's going on in printing.  Previously in this discussion
there was distinction of pixels versus dots, but I think this is
an unnecessary and misleading distinction.  Everything we have as
far as Epson printers these days are pixels. The very smallest point
on a print can contain any of 4 or 6 different gray/black inks drops,
plus with variable droplet size and overprint of multiple drops,
there are many possible gray values.  So I would call this a
pixel not a dot.  The printer 1440 and 2880 dpi specs relate
to high resolution, a few grays pixels.  Through the dithering
process we tradeoff those high resolution pixels to get pixels 
with lower resolution but more gray values.

Roy

---------------
> 
> Austin,
> 
> If the same 256 levels of gray pixels are fed to the printer and it has four
> channels each with a different shade of gray ink, it would seem to follow
> that each channel will print those 256 levels differently resulting in
> overall tonal interpolation. Lower than 1024 but greater than 256.
> 
....

> 
> I think the analogy to the pixel discussion is very apt. While we input
> pixel information to the printer is does not print pixels. The same with
> levels of gray. We may input levels but the driver and the nature of the
> inks produces an interpretation of those levels in a manner designed to
> convince our eyes that they are observing a continuous tone image.
> 
> Martin

Martin writes:

> If the same 256 levels of gray pixels are fed
> to the printer and it has four channels each
> with a different shade of gray ink, it would
> seem to follow that each channel will print
> those 256 levels differently resulting in
> overall tonal interpolation. Lower than 1024
> but greater than 256.

If an image is printed at its original resolution, the number of gray levels
will never exceed the number present in the original.  So if the original
has 256 levels, the print will have 256 levels as well.

If an image is printed at a resolution different from the original, or if it
is manipulated in any way prior to printing as part of the printing process,
the printed version may have more gray levels than the original.  The
overall quality of the printed image is never improved by this process, but
it may enhance the visual impression created by the print.  For example, if
the original has only half the resolution of the printer, the printer or its
driver may interpolate the original to produce a printable version with
higher theoretical resolution.  This interpolation will typically involve
creating new pixels that may have gray levels intermediate to those present
in the original; so an original with 256 levels may be printed as an
interpolated image with 1000 gray levels or more.  However, this doesn't
improve the quality of the image; it simply makes pixellation less obvious
in the result.

There are no circumstances in which printing with more gray levels than the
original image contained results in a better printed image (in terms of
resolution or useful tonality).  You cannot create useful information that
was not already in the original image.  There are no exceptions to this
rule; it is a consequence of information theory.

> > Tyler,
> >
> > Before responding to your post, I have one simple question for you.
> >
> > If the file only contains 256 levels of gray, and IF (BIG IF) what you
> claim
> > is true, that standard Piezo is capable of 1000 tones, where do
> the extra
> > 744 levels of gray come from?  How, exactly, are they derived?
> >
>
> Austin,
>
> If the same 256 levels of gray pixels are fed to the printer and
> it has four
> channels each with a different shade of gray ink, it would seem to follow
> that each channel will print those 256 levels differently resulting in
> overall tonal interpolation. Lower than 1024 but greater than 256.

How do you feed in 256 graytones, and now claim that each ink now has 256
graytones...that's a huge leap of something, and, at least to me, makes no
sense.

It's the combination of dithering AND the four inks that allows the number
of tones.  The four inks mean that a smaller area is needed to dither a
particular tone.

> Assume you didn't partition the inks at all. Then each channel
> would try to
> print the entire range of 256 levels. One would have a Dmax of
> 100% and the
> others say 75%, 50% and 25%. As these four channels are printed together
> wouldn't this produce intermediate levels between the 256 input levels?

You're missing my point.  I am not saying that it isn't physically
impossible to print more than 256 tones, in fact, you don't need four inks
for it...just a large enough space to allow for the number of tones, using a
dither pattern.  The point is, with a given number of input tones, how does
it derive these other tones?  There MAY be other "perceivable" (which I
doubt anyway, since I still contend that it doesn't print more than 100
anyway, nor can we distinguish much more than 100 our selves) tones...but
they weren't part of the original image.

> In
> practice the inks are partitioned so that each covers a specified
> segment of
> the 256 levels input to the driver but the crossover points
> overlap a great
> deal with multiple inks being applied in the same tonal range.

> The only way
> to I can see to get a precise 256 levels would perhaps be to use a single
> ink.

Absolutely not.  You can get any number of tones OUTPUT from any number of
inks.  It's a matter of what the driver does.  If the driver simply output
256 tones, then it outputs 256 tones, and that is not number of ink
dependant.

> I think the analogy to the pixel discussion is very apt. While we input
> pixel information to the printer is does not print pixels. The same with
> levels of gray. We may input levels but the driver and the nature of the
> inks produces an interpretation of those levels in a manner designed to
> convince our eyes that they are observing a continuous tone image.

Well, I'll go back to my claim that 1) it doesn't produce 1000 tones, that
is physically impossible, and 2) that we can't distinguish them anyway...

Austin

Roy,

> > > Tyler,
> > >
> > > Before responding to your post, I have one simple question for you.
> > >
> > > If the file only contains 256 levels of gray, and IF (BIG IF) what you
> > claim
> > > is true, that standard Piezo is capable of 1000 tones, where
> do the extra
> > > 744 levels of gray come from?  How, exactly, are they derived?
> > >
>
> Hi Austin,
>
> Sorry for joining late, but I've been away.
> Your arguments seem so self-evident that it hard to see what else is
> going on.  Say you were to create a 8 bit grayscale file with 256
> separate one inch squares such that each square contained a different
> gray value -- i.e. 0,1,2,... 255.  Each square has a different
> gray value and at least theoretically a different gray tone on the
> print --> thus there are 256 gray tones possible.  This is your
> argument, right?

No.  I simply do not believe the Piezo system prints more than 100 tones,
first off...and if I remember right, that is actually the original claim by
Jon when Piezo was first introduced...now it's magically jumped to 1000.
Secondly, I don't believe we can visually distinguish them, and thirdly, I
simply don't believe that the printers/inks/papers have the ability to print
1000 tones...the inks aren't that "pure", the ability to regulate the
droplets isn't that good...etc. to product 1000 distinguishable tones.

I completely understand residual tonality, that isn't the discussion.  There
simply isn't the tonal resolution (dynamic range if you will ;-) in the
system to print 1000 tones.  The noise is too high in the hardware alone to
make that possible.  Print a 100 step wedge, then try printing a 256 step
wedge...and measure it with the best densitometer you can find.  I guarantee
you won't get 256 separated tones, much less 1000.  The system works great
at around 100+, and that fits what we are able to see anyway...

> The tradeoff of gray levels versus resolution is really the entire
> basis of what's going on in printing.  Previously in this discussion
> there was distinction of pixels versus dots, but I think this is
> an unnecessary and misleading distinction.  Everything we have as
> far as Epson printers these days are pixels. The very smallest point
> on a print can contain any of 4 or 6 different gray/black inks drops,
> plus with variable droplet size and overprint of multiple drops,
> there are many possible gray values.  So I would call this a
> pixel not a dot.

Yeah, but it simply isn't a pixel, unless your "image" contains exactly the
values that are possible with the inks and droplet size (which is misleading
by the way), and the fact is, they don't.  The distinction between pixels
and dots is VERY important, or we would not be dithering, and the printer
driver does dither.

Austin

----- Original Message -----

From: "Anthony Atkielski" <atkielski@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, August 04, 2002 12:15 AM
Subject: Re: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> Martin writes:
>
> > If the same 256 levels of gray pixels are fed
> > to the printer and it has four channels each
> > with a different shade of gray ink, it would
> > seem to follow that each channel will print
> > those 256 levels differently resulting in
> > overall tonal interpolation. Lower than 1024
> > but greater than 256.
>
> If an image is printed at its original resolution, the number of gray
levels
> will never exceed the number present in the original.  So if the original
> has 256 levels, the print will have 256 levels as well.

Anthony,

Even when it is converted to CMYK and with six different shades of gray ink?
I think that it would be highly unlikely in any circumstance that input
exactly matched the output.
>
> If an image is printed at a resolution different from the original, or if
it
> is manipulated in any way prior to printing as part of the printing
process,
> the printed version may have more gray levels than the original.

The data is always manipulated when we print. This is the function of the
printer driver and is the only way we can print gray scale or RGB or even
CMYK files to out CMYK and CcMcYK printers. I am sure that even the dye-sub
printer drivers are manipulating the data as well.

> The overall quality of the printed image is never improved by this
process, but
> it may enhance the visual impression created by the print.

If the visual appearance of the print is enhanced then what else do we need
to be concerned about?

>  For example, if
> the original has only half the resolution of the printer, the printer or
its
> driver may interpolate the original to produce a printable version with
> higher theoretical resolution.  This interpolation will typically involve
> creating new pixels that may have gray levels intermediate to those
present
> in the original; so an original with 256 levels may be printed as an
> interpolated image with 1000 gray levels or more.  However, this doesn't
> improve the quality of the image; it simply makes pixellation less obvious
> in the result.

But it does improve the appearance of the print to the point that they are
of photographic quality. Beyond that I don't see that it matters. I am
getting more information out of my negatives by scanning them and printing
them with inkjet than I can get from my enlarger.

>
> There are no circumstances in which printing with more gray levels than
the
> original image contained results in a better printed image (in terms of
> resolution or useful tonality).  You cannot create useful information that
> was not already in the original image.  There are no exceptions to this
> rule; it is a consequence of information theory.

If the information being created results in a more pleasing print then I
would say that is the exception to the rule. This is photography and not
information theory after all and it is only the quality of the end result
that counts. The camera, negative, scanner, software and printer are all
simply tools for artistic expression. Understanding how they work is an
important part of the craft but only to the extent that it allows us to
influence the end result.

At this point I gather that most people on this list find the B&W digital
output from the inkjet printers and other technologies to be extremely
satisfying. After all that is why we are here to see what we can learn from
each other to improve our printing techniques. I believe a good portion of
us feel that the output from the inkjets and digital contact neg processes
equal or exceed traditional printing, or we would not have switched.

It seems that you do not agree and are still looking for a way to go digital
with your printing. If inkjet does not meet your own standards, why not try
one of the other approached such as contact negatives from imagesetters to
make silver prints, have enlarging negs output from a LVT or try having your
files output on one of the "laser enlargers".

Martin Wesley

--- In DigitalBlackandWhiteThePrint@y..., "Ernst Dinkla" <
e.dinkla@c...> wrote:
snip
> I was intrigued by a message from Jon Cone...
snip
> Krawitz mentions something...
snip

Hi Ernst,
I recall a very intriguing, however cloaked, conversation between Cone 
and Krawitz on the Leben list some time ago about all this. It's over 
my head I'm afraid.
My comments have all been about utilizing multiple channels and inks to 
"extend" monochromatic scale.
There is clearly much going on at the driver/printer level as well. 
That the Piezo driver addresses the printer differently than the Epson 
driver seems obvious. It's maximum allowable image area for a given 
page setup size is different, and watching the ink go down one can 
observe obvious clear bands or rows as it proceeds as opposed to the 
soft progression of ink the Epson driver puts down. I think this is 
part of the reason Jon says the driver doesn't dither. The definition 
of "dither" seems to be the problem, and in this case is more related 
to Photoshop's dither option than the actual creation of printing dots 
from pixels. I have seen RIPs that allow user adjustable "multi-pass" 
options, so there seem to be several options at driver level software 
design.
I don't pretend to know anything about that end of things, just some 
dangerous uninformed suppositions.
Tyler

----- Original Message -----

From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, August 04, 2002 7:05 AM
Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?


>
> > > Tyler,
> > >
> > > Before responding to your post, I have one simple question for you.
> > >
> > > If the file only contains 256 levels of gray, and IF (BIG IF) what you
> > claim
> > > is true, that standard Piezo is capable of 1000 tones, where do
> > the extra
> > > 744 levels of gray come from?  How, exactly, are they derived?
> > >
> >
> > Austin,
> >
> > If the same 256 levels of gray pixels are fed to the printer and
> > it has four
> > channels each with a different shade of gray ink, it would seem to
follow
> > that each channel will print those 256 levels differently resulting in
> > overall tonal interpolation. Lower than 1024 but greater than 256.
>
> How do you feed in 256 graytones, and now claim that each ink now has 256
> graytones...that's a huge leap of something, and, at least to me, makes no
> sense.

Austin,

Do you believe that the driver of a CMYK printer sends precisely 64 levels
of gray to each channel or that a CcMmYK printer sends 42.7 levels to each
channel? You know more about printer drivers than I do but this seems
unlikely. If I send 256 levels to an ink with a Dmax of 1.7 can I get 256
levels of gray, right? What if the Dmax is 1.3? 1.0? 0.5? You still have 256
levels but since the range is smaller the difference between the levels gets
smaller.
>
> It's the combination of dithering AND the four inks that allows the number
> of tones.  The four inks mean that a smaller area is needed to dither a
> particular tone.

True but I still doubt that you are getting an exact input/output match.
>
> > Assume you didn't partition the inks at all. Then each channel
> > would try to
> > print the entire range of 256 levels. One would have a Dmax of
> > 100% and the
> > others say 75%, 50% and 25%. As these four channels are printed together
> > wouldn't this produce intermediate levels between the 256 input levels?
>
> You're missing my point.  I am not saying that it isn't physically
> impossible to print more than 256 tones, in fact, you don't need four inks
> for it...just a large enough space to allow for the number of tones, using
a
> dither pattern.  The point is, with a given number of input tones, how
does
> it derive these other tones?  There MAY be other "perceivable" (which I
> doubt anyway, since I still contend that it doesn't print more than 100
> anyway, nor can we distinguish much more than 100 our selves) tones...but
> they weren't part of the original image.

The other tones are simply interpolations between any 2 of the 256 levels. I
do agree with you on the figure of 100 being a reasonable limit to what we
can readily distinguish differences in tone. Just print out a copy of
Tyler's "Z" which consists of 10 squares each containing a gradient so the
squares cover 1 to 10%, 11 to 20%, etc. There is a large "Z" in each box
that is at the mid point in the gradient. (The file is in the Files section)
It is pretty tough to distinguish between a 1% change in tone.

Prudence would make want to output something considerably higher than the
minimum though. So if 100 is close to the minimum you need to simulate
continuous tone I would be inclined to use double that but in any case 256
tones would seem to fill the bill just fine.

>
> > In
> > practice the inks are partitioned so that each covers a specified
> > segment of
> > the 256 levels input to the driver but the crossover points
> > overlap a great
> > deal with multiple inks being applied in the same tonal range.
>
> > The only way
> > to I can see to get a precise 256 levels would perhaps be to use a
single
> > ink.
>
> Absolutely not.  You can get any number of tones OUTPUT from any number of
> inks.  It's a matter of what the driver does.  If the driver simply output
> 256 tones, then it outputs 256 tones, and that is not number of ink
> dependant.

So theoretically you could get 1000 tones form 4 inks as ConeTech claims?

>
> > I think the analogy to the pixel discussion is very apt. While we input
> > pixel information to the printer is does not print pixels. The same with
> > levels of gray. We may input levels but the driver and the nature of the
> > inks produces an interpretation of those levels in a manner designed to
> > convince our eyes that they are observing a continuous tone image.
>
> Well, I'll go back to my claim that 1) it doesn't produce 1000 tones, that
> is physically impossible, and 2) that we can't distinguish them anyway...

1) Wait a minute you just said it was possible <G>, but I agree that it
probably doesn't.

2) Yes and no. If there were 1000 levels and we can only distinguish a 1%
differences in levels then in the 1000 level print we could not distinguish
between 10 and 11 or 10 and 15 but we could distinguish between 10 and 20.
We could also distinguish between 11 and 21, 12 and 22, 703 and 713 etc. So
within the 1000 levels you would have what, 990 distinguishable tonal pairs?
I think this is the value of having more than just 100 levels in a print. I
suspect that the effect of additional levels beyond 100 improves the
appearance of the print but like resolution at a certain point additional
levels do not offer improvement.

Martin

> >
> > > > Tyler,
> > > >
> > > > Before responding to your post, I have one simple question for you.
> > > >
> > > > If the file only contains 256 levels of gray, and IF (BIG
> IF) what you
> > > claim
> > > > is true, that standard Piezo is capable of 1000 tones, where do
> > > the extra
> > > > 744 levels of gray come from?  How, exactly, are they derived?
> > > >
> > >
> > > Austin,
> > >
> > > If the same 256 levels of gray pixels are fed to the printer and
> > > it has four
> > > channels each with a different shade of gray ink, it would seem to
> follow
> > > that each channel will print those 256 levels differently resulting in
> > > overall tonal interpolation. Lower than 1024 but greater than 256.
> >
> > How do you feed in 256 graytones, and now claim that each ink
> now has 256
> > graytones...that's a huge leap of something, and, at least to
> me, makes no
> > sense.
>
> Austin,
>
> Do you believe that the driver of a CMYK printer sends precisely 64 levels
> of gray to each channel or that a CcMmYK printer sends 42.7 levels to each
> channel?

Martin,

No, that's not how dithering works.  It derives a dither pattern that
consists of dot placement, and color...there is no separation into four
channels as you say.  Each ink is either a dot or not, 256 levels aren't
sent to each color ink.

> > It's the combination of dithering AND the four inks that allows
> the number
> > of tones.  The four inks mean that a smaller area is needed to dither a
> > particular tone.
>
> True but I still doubt that you are getting an exact input/output match.

Oh I agree...but I'm only questioning 1000 tones, not that you get a precise
input/output match...as I know you don't.  I only expect Piezo to give me
100 tones in fact...

> The other tones are simply interpolations between any 2 of the
> 256 levels.

That's one of my points...I simply don't believe it works that way.  I've
designed halftone/dither algorithms, and typically, the number of tones is
REDUCED from what is in the file...there isn't a tonal expansion.  This is
typically for practical reasons, as more tones takes more area, and reduces
resolution...and as I've said, more than 100 tones aren't necessarily usable
anyway.  Again, it's the 1000 number I'm questioning.  If it did 256, I'd be
happy with that...

> Prudence would make want to output something considerably higher than the
> minimum though. So if 100 is close to the minimum you need to simulate
> continuous tone I would be inclined to use double that but in any case 256
> tones would seem to fill the bill just fine.

Agreed.

> >
> > > In
> > > practice the inks are partitioned so that each covers a specified
> > > segment of
> > > the 256 levels input to the driver but the crossover points
> > > overlap a great
> > > deal with multiple inks being applied in the same tonal range.
> >
> > > The only way
> > > to I can see to get a precise 256 levels would perhaps be to use a
> single
> > > ink.
> >
> > Absolutely not.  You can get any number of tones OUTPUT from
> any number of
> > inks.  It's a matter of what the driver does.  If the driver
> simply output
> > 256 tones, then it outputs 256 tones, and that is not number of ink
> > dependant.
>
> So theoretically you could get 1000 tones form 4 inks as ConeTech claims?

We are talking about two different things.  The INPUT file is 8 bits, which
is 256 tones, period.  The fact that you can make as many tones as you want
with a dither pattern and one or multiple inks isn't in question.  Whether
Piezo DOES it or not is what's in question.  It simply isn't practical as
far as I can tell.

> >
> > > I think the analogy to the pixel discussion is very apt.
> While we input
> > > pixel information to the printer is does not print pixels.
> The same with
> > > levels of gray. We may input levels but the driver and the
> nature of the
> > > inks produces an interpretation of those levels in a manner
> designed to
> > > convince our eyes that they are observing a continuous tone image.
> >
> > Well, I'll go back to my claim that 1) it doesn't produce 1000
> tones, that
> > is physically impossible, and 2) that we can't distinguish them
> anyway...
>
> 1) Wait a minute you just said it was possible <G>, but I agree that it
> probably doesn't.

It is THEORETICALLY possible, but not with this particular system.  There is
probably too much variance in the ink tonality, as well as the ability to
control drop size that would limit it.

> I
> suspect that the effect of additional levels beyond 100 improves the
> appearance of the print but like resolution at a certain point additional
> levels do not offer improvement.

I agree with that, but not 1000.

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <
darkroom@i...> wrote:
snip
> How do you feed in 256 graytones, and now claim that each ink now has 256
> graytones...that's a huge leap of something, and, at least to me, makes no
> sense.
Austin, it is simple, there are a number of ways. You simply duplicate 
the channel and print through a multiple channel driver. With a 4 
channel RIP as I use, it's all done in Photoshop, there are a few 
different techniques. But no information is lost when duplicating 
channels. Very easy in 8 bit, 16 bit a little more complicated.
I think part of the lack of connection here is that you see before you 
a single channel grayscale file. All of my comments regard the use of 
multiple channels to multiple inks. Specifically how the Piezo driver 
is doing it invisibly I have no knowlege of, but again, it is a 
multiple channel driver driving multiple inks. Assigning different 
portions of tone (even the same tones) from a single channel file to 
the different channels (and their subsequent inks) is accomplished one 
way or another whether you like it or not. It is also clear that each 
channel is being heavily manipulated, you can't assign the inks to 
their proper parts of the scale for a dotless look without doing so.

The whole subject of driver/printer interpolation beyond the 
manipulation of multiple inks I haven't even touched. But it may be far 
more relevant than my BS.

> Well, I'll go back to my claim that 1) it doesn't produce 1000 tones, that
> is physically impossible, and 2) that we can't distinguish them anyway...

So then, what were we talking about???
Tyler

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <
darkroom@i...> wrote:
> > Austin,
> >
> > Do you believe that the driver of a CMYK printer sends precisely 64 levels
> > of gray to each channel or that a CcMmYK printer sends 42.7 levels to each
> > channel?
> 
> Martin,
> 
> No, that's not how dithering works.  It derives a dither pattern that
> consists of dot placement, and color...there is no separation into four
> channels as you say.  Each ink is either a dot or not, 256 levels aren't
> sent to each color ink.
That's where we part Austin. I'm repeatedly discussing an aproach that 
depends on the ability to do precisely that. We are far from the 
dithering stage yet. I can easily manipulate a single channel grayscale 
256 level file into a four channel file with all 256 original tones in 
all four channels precisely. And I can send that file to a printer and 
get exactly that on paper, all the way from 0 to 400% ink.
There is no concievable reason to do so, but the system would allow it.

> input/output match...as I know you don't.  I only expect Piezo to give me
> 100 tones in fact...
I'm certainly glad it gives you more. The 1% change at the border of 
each box to the next in the Z's file is clearly visible on paper.
Tyler

ok, are we boring everyone here to tears yet? At least it hasn't caught 
up with the D60 (or whatever it was) thread.

Tyler,

> > How do you feed in 256 graytones, and now claim that each ink
> now has 256
> > graytones...that's a huge leap of something, and, at least to
> me, makes no
> > sense.
> Austin, it is simple, there are a number of ways. You simply duplicate
> the channel and print through a multiple channel driver.

I believe you're missing my point...  I KNOW that there are many ways of
"creating" intermediate tones...  I simply don't believe Piezo prints 1000
tones, period.  It's a physical impossibility in the system we are using.
There are too many variances in the control of many aspects of this, that
doing so is impossible, in my estimation...and no, I haven't proven so...but
it, for me, is simply practical reality.

As I've suggested.  Make a 256 tone Z pattern....and see if you can
distinguish all 256 tones.  Then do a 512 etc.  SEE if it does it.  The 100
Z pattern is barely discernable over all 100 tones, some more
distinguishable than others...and that leads me to believe that a pattern
10x that would not be discernable at all.

It's interesting that the "Proof of Piezography" only has %5 and %1 tonal
variation...if it was capable of %.1 variations, then I'd expect they would
want to "show it off"...

Austin

Ok, I'll play the Village idiot hear. I beleive Piezo prints may not show 1% 
Variations, but I do believe they show 2% variations that are visable in real 
life! at least in the 1-5% range and the 95-100% range. I now routinely 
measure my Highlight and shadows in these ranges as I absolutley need a 2% 
highlight in my Highkey gradient Backgrounds. 1% is too close to paper white 
but 2% is not. Same with 98%and 100% on the black end. 
Austin , so you beleive the Claims of Piezography to be impossible?
Steve Meyers




In a message dated 08/04/2002 12:26:27 PM Pacific Daylight Time, 
darkroom@... writes:


> It's interesting that the "Proof of Piezography" only has %5 and %1 tonal
> variation...if it was capable of %.1 variations, then I'd expect they would
> want to "show it off"...
> 
> Austin
> 




[Non-text portions of this message have been removed]

Er, Steve...Piezo does show %1 variations in tone, but that's only 100
tones...if it only showed %2 variations in tones, that would be 50 tones...

Austin

> Ok, I'll play the Village idiot hear. I beleive Piezo prints may
> not show 1%
> Variations, but I do believe they show 2% variations that are
> visable in real
> life! at least in the 1-5% range and the 95-100% range. I now routinely
> measure my Highlight and shadows in these ranges as I absolutley
> need a 2%
> highlight in my Highkey gradient Backgrounds. 1% is too close to
> paper white
> but 2% is not. Same with 98%and 100% on the black end.
> Austin , so you beleive the Claims of Piezography to be impossible?
> Steve Meyers
>
>
> > It's interesting that the "Proof of Piezography" only has %5
> and %1 tonal
> > variation...if it was capable of %.1 variations, then I'd
> expect they would
> > want to "show it off"...
> >
> > Austin
>

My instinct told me to stay out of this;) Sorry I didn't see the Decimal 
point in your previous "proof of piezography" post. as in .1% Still, you 
beleive the claims of Piezography to be impossible?
Steve M.

In a message dated 08/04/2002 1:20:17 PM Pacific Daylight Time, 
darkroom@... writes:


> Er, Steve...Piezo does show %1 variations in tone, but that's only 100
> tones...if it only showed %2 variations in tones, that would be 50 tones...
> 
> Austin
> 




[Non-text portions of this message have been removed]

Hi Steve,

From a practical standpoint, 1000 tones, no way...

Regards,

Austin

> -----Original Message-----
> From: sdmey4@... [mailto:sdmey4@...]
> Sent: Sunday, August 04, 2002 4:43 PM
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: Re: [Digital BW] Number of tones was Re: Do inkjets dither or
> not?
> 
> 
> My instinct told me to stay out of this;) Sorry I didn't see the Decimal 
> point in your previous "proof of piezography" post. as in .1% Still, you 
> beleive the claims of Piezography to be impossible?
> Steve M.
> 
> In a message dated 08/04/2002 1:20:17 PM Pacific Daylight Time, 
> darkroom@... writes:
> 
> 
> > Er, Steve...Piezo does show %1 variations in tone, but that's only 100
> > tones...if it only showed %2 variations in tones, that would be 
> 50 tones...
> > 
> > Austin
> >

Martin writes:

> Even when it is converted to CMYK and with
> six different shades of gray ink?

Conversion involves interpolation.  The rule holds only for situations that
do not involve interpolation (such as constant resolution and no change in
color space).

> If the visual appearance of the print is enhanced
> then what else do we need to be concerned about?

It's important to not confuse the visual impression created by an image with
its information content.

Unsharp masking, for example, creates the impression of greater
sharpness--and yet in reality it degrades image quality.

> But it does improve the appearance of the print
> to the point that they are of photographic quality.

There's no such thing as "photographic quality."  It's just a marketing
buzzword.

> If the information being created results in a
> more pleasing print then I would say that is
> the exception to the rule.

If you extend that logic, you may as well paint the scene instead of
photographing.  Photography's distinction is that it draws upon images that
accurately represent reality; remove that, and it's not photography any
more.

> This is photography and not information theory
> after all and it is only the quality of the end
> result that counts.

Quality in photography is fidelity to reality.  Other aspects of photography
may be artistic, but they are not quality.

> The camera, negative, scanner, software and printer
> are all simply tools for artistic expression.

If that's all they are, why not just use a paintbrush.

There are other uses for photography besides artistic expression.
Communication is one of them.

> It seems that you do not agree and are still
> looking for a way to go digital with your printing.

Neither.  I'm just putting things into perspective.

> If inkjet does not meet your own standards ...

My standards vary depending on my intended use.

--- In DigitalBlackandWhiteThePrint@y..., "Anthony Atkielski" <
atkielski@c...> wrote:
> Martin writes:
> 
> > Even when it is converted to CMYK and with
> > six different shades of gray ink?
> 
> Conversion involves interpolation

Well, to make too fine a point of it, not necessarily.
Tyler

Tyler writes:

> Well, to make too fine a point of it, not necessarily.

A one-to-one conversion does not involve interpolation (such as inverting
colors in Photoshop).

Anthony Wrote:
> photographing.  Photography's distinction is that it draws upon images that
> accurately represent reality; remove that, and it's not photography any
> more.

 some who play with abstract use of light and shadow as a means of
expressing themselves do not represent reality... but it's still
camera/film/chemistry and ultimately a print. I'm curious, what is that if
not photography.

Carolyn

----- Original Message -----

From: "Anthony Atkielski" <atkielski@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, August 04, 2002 4:34 PM
Subject: Re: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> Martin writes:
>
> > Even when it is converted to CMYK and with
> > six different shades of gray ink?
>
> Conversion involves interpolation.  The rule holds only for situations
that
> do not involve interpolation (such as constant resolution and no change in
> color space).

Anthony,

Since there is always conversion of the data via the driver then there is
always interpolation (or interpretation) of the image data in the making of
the print.
>
> > If the visual appearance of the print is enhanced
> > then what else do we need to be concerned about?
>
> It's important to not confuse the visual impression created by an image
with
> its information content.

Why? The end print is all that ultimately counts. If it looks good and
matches your intent in making the print, it is good.
>
> Unsharp masking, for example, creates the impression of greater
> sharpness--and yet in reality it degrades image quality.

The amount of sharpening to use is a subjective judgment. Some people like a
little sharpening, some a lot and some not at all. Artistic decision.
>
> > But it does improve the appearance of the print
> > to the point that they are of photographic quality.
>
> There's no such thing as "photographic quality."  It's just a marketing
> buzzword.

No marketing involved just my personal assessment of the current quality of
the prints.
>
> > If the information being created results in a
> > more pleasing print then I would say that is
> > the exception to the rule.
>
> If you extend that logic, you may as well paint the scene instead of
> photographing.  Photography's distinction is that it draws upon images
that
> accurately represent reality; remove that, and it's not photography any
> more.

I am a terrible painter. Photography accurately represents reality? Ha! It
is always an interpretation of reality be it Ansel Adams, Walker Evans or
Jerry Uelsmann.
>
> > This is photography and not information theory
> > after all and it is only the quality of the end
> > result that counts.
>
> Quality in photography is fidelity to reality.  Other aspects of
photography
> may be artistic, but they are not quality.

Quality equals fidelity to reality?!? So a perfect print of a shot of a
neutral gray density card is a quality photograph. Well you are entitled to
your opinion but my interest in photography is as an art form.
>
> > The camera, negative, scanner, software and printer
> > are all simply tools for artistic expression.
>
> If that's all they are, why not just use a paintbrush.

Because I want to make a photograph and not a painting. Give me a break. If
they are not tools what are they?
>
> There are other uses for photography besides artistic expression.
> Communication is one of them.

Artistic express is generally held to be a form of communication.
>
> > It seems that you do not agree and are still
> > looking for a way to go digital with your printing.
>
> Neither.  I'm just putting things into perspective.

In perspective to what?
>
> > If inkjet does not meet your own standards ...
>
> My standards vary depending on my intended use.

Well what are your intended uses?

Martin Wesley

> I'm curious, what is that if not photography.

It does have a name of its own, but I've forgotten it.

> 
>> I'm curious, what is that if not photography.
> 
> It does have a name of its own, but I've forgotten it.

photo-impressionism perhaps? for some anyway, although mine doesn't quite
fit there either.  It's still photography in my opinion.

Carolyn

Hi Anthony,

> > Even when it is converted to CMYK and with
> > six different shades of gray ink?
>
> Conversion involves interpolation.  The rule holds only for
> situations that
> do not involve interpolation (such as constant resolution and no change in
> color space).

Or decimation...

> > If the visual appearance of the print is enhanced
> > then what else do we need to be concerned about?
>
> It's important to not confuse the visual impression created by an
> image with
> its information content.
>
> Unsharp masking, for example, creates the impression of greater
> sharpness--and yet in reality it degrades image quality.

I agree with that.

> > If the information being created results in a
> > more pleasing print then I would say that is
> > the exception to the rule.
>
> If you extend that logic, you may as well paint the scene instead of
> photographing.  Photography's distinction is that it draws upon
> images that
> accurately represent reality; remove that, and it's not photography any
> more.
>
> > This is photography and not information theory
> > after all and it is only the quality of the end
> > result that counts.
>
> Quality in photography is fidelity to reality.  Other aspects of
> photography
> may be artistic, but they are not quality.

To some degree, I agree with what you've said above.

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> Roy,
> 
> > > > Tyler,
> > > >
> > > > Before responding to your post, I have one simple question for you.
> > > >
> > > > If the file only contains 256 levels of gray, and IF (BIG IF) what you
> > > claim
> > > > is true, that standard Piezo is capable of 1000 tones, where
> > do the extra
> > > > 744 levels of gray come from?  How, exactly, are they derived?
> > > >
> >
> > Hi Austin,
> >
> > Sorry for joining late, but I've been away.
> > Your arguments seem so self-evident that it hard to see what else is
> > going on.  Say you were to create a 8 bit grayscale file with 256
> > separate one inch squares such that each square contained a different
> > gray value -- i.e. 0,1,2,... 255.  Each square has a different
> > gray value and at least theoretically a different gray tone on the
> > print --> thus there are 256 gray tones possible.  This is your
> > argument, right?
> 
> No.  I simply do not believe the Piezo system prints more than 100 tones,
> first off...and if I remember right, that is actually the original claim by
> Jon when Piezo was first introduced...now it's magically jumped to 1000.
> Secondly, I don't believe we can visually distinguish them, and thirdly, I
> simply don't believe that the printers/inks/papers have the ability to print
> 1000 tones...the inks aren't that "pure", the ability to regulate the
> droplets isn't that good...etc. to product 1000 distinguishable tones.

Austin,

I really don't think the Piezo system is any better than you think it is.
I agree that our eyes can only discern on the order of 100 tones so it's
kind of a moot point.  The main point was that the 256 levels i.e. 8-bit
files are only loosely connected with how many tones you can measure.
Since we're talking 1000 tones we certainly can't be talking about human
discernable tones -- we have to be using a high resolution densitometer
or the equivalent.  In the original Piezo quote there's no mention of
input or output resolution, nor detector specs, nor size of samples.
So its at least conceivable that each tone measurement is an average
of multiple input file pixels so the number could easily be greater than
256 tones.   

You wrote the following.  I'm saying the same thing "any number of tones
by dithering".

Austin>> Then you're missing the point of dithering. You can represent ANY number of
Austin>> tones by dithering, it's simply the area that it takes to do so...you simply
Austin>> need to stand further away ;-) 

> 
> I completely understand residual tonality, that isn't the discussion.  There
> simply isn't the tonal resolution (dynamic range if you will ;-) in the
> system to print 1000 tones.  The noise is too high in the hardware alone to
> make that possible.  Print a 100 step wedge, then try printing a 256 step
> wedge...and measure it with the best densitometer you can find.  I guarantee
> you won't get 256 separated tones, much less 1000.  The system works great
> at around 100+, and that fits what we are able to see anyway...

I've got a "good" densitometer not the best.  So I took one of the original
step wedges from using Piezo, put the top gradient under the densitometer.
Paper white is set at 0, the darkest was at 147.  Sliding the paper gradually
thru the meter, the densities just count up, 0,1,2,... easily hitting each
integer value.   So not surprisingly it looks like I have 148 gray tones.
Are there really 148 tones there?  It looks to me like all I've shown is
the resolution of the densitometer.  If I had another decimal digit on would
I get 1480 tones?  I really don't know, probably not.  But I'd bet I could
get a lot higher than 148.

> 
> > The tradeoff of gray levels versus resolution is really the entire
> > basis of what's going on in printing.  Previously in this discussion
> > there was distinction of pixels versus dots, but I think this is
> > an unnecessary and misleading distinction.  Everything we have as
> > far as Epson printers these days are pixels. The very smallest point
> > on a print can contain any of 4 or 6 different gray/black inks drops,
> > plus with variable droplet size and overprint of multiple drops,
> > there are many possible gray values.  So I would call this a
> > pixel not a dot.
> 
> Yeah, but it simply isn't a pixel, unless your "image" contains exactly the
> values that are possible with the inks and droplet size (which is misleading

What difference does it make what values they have?  The point is
that there are multiple gray values.  I just figure if there are 
more than 2 values (black and white) it's better described
as a pixel not a dot.

> by the way), and the fact is, they don't.  The distinction between pixels
> and dots is VERY important, or we would not be dithering, and the printer
> driver does dither.

What's the distinction?  You can and do dither either one.  Dithering just
increases the number of gray tones while sacrificing some resolution.
You can go from 2 to 256, 10 to 256, 256 to 1000.

> 
> Austin

Roy

Hi Roy,

> The main point was that the 256 levels i.e. 8-bit
> files are only loosely connected with how many tones you can measure.

Measuring them or not isn't the point.  The point is, how are they derived,
if they are even derived at all.

> In the original Piezo quote there's no mention of
> input or output resolution,

I believe that on the Piezo email list, 100 tones was what the discussion
was.

> I've got a "good" densitometer not the best.  So I took one of
> the original
> step wedges from using Piezo, put the top gradient under the densitometer.
> Paper white is set at 0, the darkest was at 147.  Sliding the
> paper gradually
> thru the meter, the densities just count up, 0,1,2,... easily hitting each
> integer value.   So not surprisingly it looks like I have 148 gray tones.

But did the printer intentionally print 148?  I don't believe so.  That's
inconsistency in the systems ability to represent a tone...and is an
important part of my point.

> > > The tradeoff of gray levels versus resolution is really the entire
> > > basis of what's going on in printing.  Previously in this discussion
> > > there was distinction of pixels versus dots, but I think this is
> > > an unnecessary and misleading distinction.  Everything we have as
> > > far as Epson printers these days are pixels. The very smallest point
> > > on a print can contain any of 4 or 6 different gray/black inks drops,
> > > plus with variable droplet size and overprint of multiple drops,
> > > there are many possible gray values.  So I would call this a
> > > pixel not a dot.
> >
> > Yeah, but it simply isn't a pixel, unless your "image" contains
> exactly the
> > values that are possible with the inks and droplet size (which
> is misleading
>
> What difference does it make what values they have?

Everything.  A pixel has a range of values.  A dot does not.  A dot is
simply a dot...and it can only contain one of the colors of available ink.

> The point is
> that there are multiple gray values.

Not for one single dot.

> The distinction
> between pixels
> > and dots is VERY important, or we would not be dithering, and
> the printer
> > driver does dither.
>
> What's the distinction?  You can and do dither either one.

You can not dither a dot.

Austin

Well, Austin, all I can say is "Huh?".    
All the answers seems to have missed the issue.

Roy

-----------
--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" 
<darkroom@i...> wrote:
> Hi Roy,
> 
> > The main point was that the 256 levels i.e. 8-bit
> > files are only loosely connected with how many tones you 
can measure.
> 
> Measuring them or not isn't the point.  The point is, how are 
they derived,
> if they are even derived at all.
> 
> > In the original Piezo quote there's no mention of
> > input or output resolution,
> 
> I believe that on the Piezo email list, 100 tones was what the 
discussion
> was.
> 
> > I've got a "good" densitometer not the best.  So I took one of
> > the original
> > step wedges from using Piezo, put the top gradient under the 
densitometer.
> > Paper white is set at 0, the darkest was at 147.  Sliding the
> > paper gradually
> > thru the meter, the densities just count up, 0,1,2,... easily 
hitting each
> > integer value.   So not surprisingly it looks like I have 148 gray 
tones.
> 
> But did the printer intentionally print 148?  I don't believe so.  
That's
> inconsistency in the systems ability to represent a tone...and is 
an
> important part of my point.
> 
> > > > The tradeoff of gray levels versus resolution is really the 
entire
> > > > basis of what's going on in printing.  Previously in this 
discussion
> > > > there was distinction of pixels versus dots, but I think this 
is
> > > > an unnecessary and misleading distinction.  Everything 
we have as
> > > > far as Epson printers these days are pixels. The very 
smallest point
> > > > on a print can contain any of 4 or 6 different gray/black 
inks drops,
> > > > plus with variable droplet size and overprint of multiple 
drops,
> > > > there are many possible gray values.  So I would call this 
a
> > > > pixel not a dot.
> > >
> > > Yeah, but it simply isn't a pixel, unless your "image" 
contains
> > exactly the
> > > values that are possible with the inks and droplet size 
(which
> > is misleading
> >
> > What difference does it make what values they have?
> 
> Everything.  A pixel has a range of values.  A dot does not.  A 
dot is
> simply a dot...and it can only contain one of the colors of 
available ink.
> 
> > The point is
> > that there are multiple gray values.
> 
> Not for one single dot.
> 
> > The distinction
> > between pixels
> > > and dots is VERY important, or we would not be dithering, 
and

> > the printer
> > > driver does dither.
> >
> > What's the distinction?  You can and do dither either one.
> 
> You can not dither a dot.
> 
> Austin

----- Original Message -----

From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, August 05, 2002 7:08 PM
Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> My interest is if Piezo can even print near that many tones as he has
> claimed (1000), as well as can we even see them....as well as, if it does,
> how does it derive them.  His comment had nothing to do with that,
> unfortunately.

The physical aspects of bringing ink on paper; bleed etc, that makes it
difficult to get the desired 256 tones on paper are at least spread over 4
grey inks. Unlike with full colour there's no need to get a max of 3 dots of
each at the same spot/area so less bleed. I doubt you can just multiply the
256 x 4, but there is of course an advantage. The use of the different greys
isn't divided that strict over percentage ranges and they will weave into
one another at the boundaries. Even if they overlap till half the next grey
then the total ink amount is much lower than in CMYK printing. Say all the
inks starts at 1 % and end at 80 % (unlikely it will be more complex), then
there still is a spread possible of approx 200 x 4. We don't see them, most
paper/ink combinations will not even make them but in theory with the best
paper/ink combination possible they can be printed. Whether the extra greys
steps input were available with a 16 bit image or by interpolation in the
driver stage doesn't matter. Of course the last builds on less information
than the first but that can be done quite clever.

Ernst

Roy,

What do YOU believe "the issue" is that I missed?

You clearly said what your "main point" was ("The main point was that the
256 levels i.e. 8-bit
files are only loosely connected with how many tones you can measure."), and
it is a point that was not in dispute at all, and wasn't the main issue I
was discussing.  It was now those tones were derived that was being
discussed.

You then made another "point" (which you clearly stated was "the point"),
which I disagree with...about the distinction between dots and pixels.

I believe my response is quite to the issues that were being discussed for a
few days here already, and I believed you were discussing the same issue...
I'm not saying it is, but did you even think it might have been you who
missed the issue?

Austin

> Well, Austin, all I can say is "Huh?".
> All the answers seems to have missed the issue.
>
> Roy

I did get a response from Jon Cone on the dithering.  His comment was
basically that "a dither pattern was not visually evident", and secondly
that it "does not use a dither pattern in the traditional sense...PiezoBW
does not use static screening techniques"...

He seems to want to distinguish his dithering technique from any other
dithering technique...and I guess his claim is his way of doing that...

Austin

I'm curious how you have mastered the ability to know what another persons
reality is. It may not be the same as yours, believe it or not. When you
shoot a photo you are, at that point abstracting a slice of what's around
you. What you decide to photograph becomes your reality or abstraction, not
everyone else's. At that point you have matched the data of your experiences
including the way you have been taught to see. This becomes your picture of
the world. Without going into too much detail, you then persuade yourself
that these pictures which are inside your head  corresponds to the world
outside. My world seems to have been a little more abstract than yours. I
get the feeling that you have a large collection of Kenny G CD's

Barry
----- Original Message -----
From: "Anthony Atkielski" <atkielski@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, August 04, 2002 8:09 PM
Subject: Re: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> > I'm curious, what is that if not photography.
>
> It does have a name of its own, but I've forgotten it.
>
>
> Please visit the Group Homepage to check the Files, Bookmarks, Polls and
other resources as they are often being updated. The page is at:
>
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
>
> If you wish to receive no emails or just a daily digest, or you wish to
unsubscribe, please edit your Membership preferences by visiting this same
page.
>
> Please follow these basic guidelines:
> - Include your full name with your message.
> - Include the address of your website, if you have one.
> - As threads develop, trim off excess portions of earlier messages to keep
them short.
> - As the topic of a thread changes remember to change the subject header.
> - Good manners are required at all time. No personal attacks or
&amp;amp;quot;flames.&amp;amp;quot;
> - Complete your Yahoo profile.
> - Before posting a question, search the message archives and the various
resources on the homepage.

>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

> I
> get the feeling that you have a large collection of Kenny G CD's
>
> Barry

Barry,

No need to get THAT nasty.  At least you didn't accuse him of having a large
collection of John Tess...

;-)

Austin

I did but took it off in the interest of good taste and civility. Life must
be extremely boring sometimes. To not understand the language of vision is
to not see the cinematography in "Citizen Cane"

Barry
----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, August 05, 2002 10:42 AM
Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?


>
> > I
> > get the feeling that you have a large collection of Kenny G CD's
> >
> > Barry
>
> Barry,
>
> No need to get THAT nasty.  At least you didn't accuse him of having a
large
> collection of John Tess...
>
> ;-)
>
> Austin
>
>
> Please visit the Group Homepage to check the Files, Bookmarks, Polls and
other resources as they are often being updated. The page is at:
>
> http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint
>
> If you wish to receive no emails or just a daily digest, or you wish to
unsubscribe, please edit your Membership preferences by visiting this same
page.
>
> Please follow these basic guidelines:
> - Include your full name with your message.
> - Include the address of your website, if you have one.
> - As threads develop, trim off excess portions of earlier messages to keep
them short.
> - As the topic of a thread changes remember to change the subject header.
> - Good manners are required at all time. No personal attacks or
&amp;amp;quot;flames.&amp;amp;quot;
> - Complete your Yahoo profile.
> - Before posting a question, search the message archives and the various
resources on the homepage.

>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

----- Original Message -----

From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, August 05, 2002 6:15 AM
Subject: RE: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> I did get a response from Jon Cone on the dithering.  His comment was
> basically that "a dither pattern was not visually evident", and secondly
> that it "does not use a dither pattern in the traditional sense...PiezoBW
> does not use static screening techniques"...
>
> He seems to want to distinguish his dithering technique from any other
> dithering technique...and I guess his claim is his way of doing that...
>
Austin,

You left out the portion of his post where he said,

"One is input (your file). One is output (the printer driver.) You are
thinking of an output driver only as an input translator. Where a lot of
these gray values go is towards averaging and smoothing (not just specific
tone reproduction). PiezoBW looks pretty damn good. There is a lot more to
PiezoBW than just translating an input value to
an output value."

This is along the lines of what Tyler, myself and others have been saying on
this thread. The driver, printer, ink and paper gives you an interpretation
of the input file and if it give good results the technical specifics may
not be all that important to us.

Martin

> > I did get a response from Jon Cone on the dithering.  His comment was
> > basically that "a dither pattern was not visually evident", and secondly
> > that it "does not use a dither pattern in the traditional
> sense...PiezoBW
> > does not use static screening techniques"...
> >
> > He seems to want to distinguish his dithering technique from any other
> > dithering technique...and I guess his claim is his way of doing that...
> >
> Austin,
>
> You left out the portion of his post where he said,
>
> "One is input (your file). One is output (the printer driver.) You are
> thinking of an output driver only as an input translator. Where a lot of
> these gray values go is towards averaging and smoothing (not just specific
> tone reproduction). PiezoBW looks pretty damn good. There is a lot more to
> PiezoBW than just translating an input value to
> an output value."
>
> This is along the lines of what Tyler, myself and others have
> been saying on
> this thread. The driver, printer, ink and paper gives you an
> interpretation
> of the input file and if it give good results the technical specifics may
> not be all that important to us.

Martin,

Sorry, but <sigh>.

It's also EXACTLY what I've been saying too...the fact that the tonality
isn't mapped 1:1 via "dithering" is undisputable, and has never been an
issue with me.  What Jon said didn't answer my question.

My interest is if Piezo can even print near that many tones as he has
claimed (1000), as well as can we even see them....as well as, if it does,
how does it derive them.  His comment had nothing to do with that,
unfortunately.

The reason I didn't post that part of his post is because it is still
inconclusive, and I've asked more questions of him to try to get answers to
this.  The dithering part, I believe, he has answered as well as he's going
to answer it.

Regards,

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> 
> 
> > > I did get a response from Jon Cone on the dithering.  His comment was
> > > basically that "a dither pattern was not visually evident", and secondly
> > > that it "does not use a dither pattern in the traditional
> > sense...PiezoBW
> > > does not use static screening techniques"...
> > >
> > > He seems to want to distinguish his dithering technique from any other
> > > dithering technique...and I guess his claim is his way of doing that...
> > >
> > Austin,
> >
> > You left out the portion of his post where he said,
> >
> > "One is input (your file). One is output (the printer driver.) You are
> > thinking of an output driver only as an input translator. Where a lot of
> > these gray values go is towards averaging and smoothing (not just specific
> > tone reproduction). PiezoBW looks pretty damn good. There is a lot more to
> > PiezoBW than just translating an input value to
> > an output value."
> >
> > This is along the lines of what Tyler, myself and others have
> > been saying on
> > this thread. The driver, printer, ink and paper gives you an
> > interpretation
> > of the input file and if it give good results the technical specifics may
> > not be all that important to us.
> 
> Martin,
> 
> Sorry, but <sigh>.
> 
> It's also EXACTLY what I've been saying too...the fact that the tonality
> isn't mapped 1:1 via "dithering" is undisputable, and has never been an
> issue with me.  What Jon said didn't answer my question.
> 
> My interest is if Piezo can even print near that many tones as he has
> claimed (1000), as well as can we even see them....as well as, if it does,
> how does it derive them.  His comment had nothing to do with that,
> unfortunately.

Austin,

Well I don't feel quite so bad, Jon Cone gave you the same answer as I 
did and again you missed it.   I'll try one more time.

Just so we're talking the same issue, I'll restate it:
The input file is 8-bit which means each pixel has 1 of 256 possible values.
Piezo has claimed "more than 1000 gray values".  You have repeatedly
stated that its impossible to get 1000 values from an 8-bit pixel.
Clearly you can't, but no one ever claimed you could.  The Piezo system
gray values on a print.  The only place that contains "1000 gray values"
is the print.  What can that possibly mean?  You use a densitometer of
sufficient quality and look for different values.  As you go over the whole
print if you can come up with 1000 different density numbers then the
"1000 gray values" criteria has been satisfied.  So, is this at all possible
given an 8-bit input file?  Sure, it's quite easy.  All you need is the
densitometer to be reading an area that is (as you say) derived from
4 pixels of the original file.   In going from a value 102 to a value 103,
by averaging 4 pixels you can get 102, 102.25, 102.5, 102.75, 103.
This gives you 4 gray values for each input pixel level so 
4*256 = 1024 gray values.  This is what Jon Cone meant when he said: 
 "Where a lot of these gray values go is towards averaging and smoothing."

Roy

> 
> The reason I didn't post that part of his post is because it is still
> inconclusive, and I've asked more questions of him to try to get answers to
> this.  The dithering part, I believe, he has answered as well as he's going
> to answer it.
> 
> Regards,
> 
> Austin

on 8/5/02 2:15 PM, royvharrington wrote:

> Just so we're talking the same issue, I'll restate it:
> The input file is 8-bit which means each pixel has 1 of 256 possible values.
> Piezo has claimed "more than 1000 gray values".  You have repeatedly
> stated that its impossible to get 1000 values from an 8-bit pixel.
> Clearly you can't, but no one ever claimed you could.  The Piezo system
> gray values on a print.  The only place that contains "1000 gray values"
> is the print.  What can that possibly mean?  You use a densitometer of
> sufficient quality and look for different values.  As you go over the whole
> print if you can come up with 1000 different density numbers then the
> "1000 gray values" criteria has been satisfied.

Careful Roy, those extra tones would be considered noise. By Austin's
definition, that much noise would point of a print of really low DyR. No
wait, by Austin's definition, lot's of tones means high DyR...I'm
confused...Austin?

Come on folks, you all knew this was a dynamic range conversation waiting to
happen.  ;-)

Todd

> 
> Come on folks, you all knew this was a dynamic range conversation waiting to
> happen.  ;-)


Oh man Todd, you can't be that bored!

Carolyn

Carolyn Frayn wrote:

>>Come on folks, you all knew this was a dynamic range conversation waiting to
>>happen.  ;-)
>>    
>>
>
>
>Oh man Todd, you can't be that bored!
>
>
>  
>
Back to the issue of NUMBER of tones...

The baseline for measuring tones HAS to be the human eye..  Otherwise it 
doesn't make much sense, right?  I mean we could theoretically design 
color spaces that incorporate the IR and UV portions of spectra, but 
they wouldn't add a single tone the human eye could discern..

IF Cone and others are creating tones the human eye can't distinguish 
form another tone, who the HELL CARES?

PLUS, the standard FOR differences between tones is WHETHER the human 
eye can discern them as different..  Accordingly, if 4000 plus tones can 
be measured as different by a high quality spectro, BUT the human eye 
cannot differentiate them..  They simply ARE NOT 4000 different tones.. 
They ARE only however many different tones the human eye could discern 
out of a 4000 swatch sample of those tones..

PS - I refuse to start making prints FOR butterflies and bumblebees... 
The ubiquitous and smarmy prints OF butterflies and bumblebees 
throughout the interiors and furnishing market are bad enough..  ;-)
Keith
 
 



[Non-text portions of this message have been removed]

To make my point crystal clear...

If humans only could see Cyan and Magenta, all tones would have to be 
made up of discernible combinations of those colors..

The amount of Yellow in an image would not matter a whit in deciding how 
many tones there were..

Keith

--- In DigitalBlackandWhiteThePrint@y..., Todd Flashner <tflash@e...> wrote:
> on 8/5/02 2:15 PM, royvharrington wrote:
> 
> > Just so we're talking the same issue, I'll restate it:
> > The input file is 8-bit which means each pixel has 1 of 256 possible values.
> > Piezo has claimed "more than 1000 gray values".  You have repeatedly
> > stated that its impossible to get 1000 values from an 8-bit pixel.
> > Clearly you can't, but no one ever claimed you could.  The Piezo system
> > gray values on a print.  The only place that contains "1000 gray values"
> > is the print.  What can that possibly mean?  You use a densitometer of
> > sufficient quality and look for different values.  As you go over the whole
> > print if you can come up with 1000 different density numbers then the
> > "1000 gray values" criteria has been satisfied.
> 
> Careful Roy, those extra tones would be considered noise.

No, Todd, they are just in the interest of smoothing the output and
giving the perception of a continuous tone print.  It's really amazing how
many people are fixated on a digital, discrete input file producing a print
composed of digital, discrete, distinguishable gray values and how many
of those tones there are.  The whole point of all the piezo effort, the
quad ink effort, and the vm curves effort is to produce prints that 
have no visible discreteness -- i.e. are perceived as continuous tone.

The whole marketing point of the Piezo 1000 gray value claim is that it
way higher than humanly discernable so you are assured of being able
to have a smooth transition between any tonal values.

 By Austin's
> definition, that much noise would point of a print of really low DyR. No
> wait, by Austin's definition, lot's of tones means high DyR...I'm
> confused...Austin?
> 
> Come on folks, you all knew this was a dynamic range conversation waiting to
> happen.  ;-)

Bad joke!! You must be confused.  ;-)

> 
> Todd

Roy

--- In DigitalBlackandWhiteThePrint@y..., "Editor P.O.V. Image Service" <editor@p...> wrote:
snip
> IF Cone and others are creating tones the human eye can't distinguish 
> form another tone, who the HELL CARES?

I do.
Well done B&W inkjet prints look great, I've certainly committed to pursuing this form of reproduction for my work.
But,
When I look at a masterfully created silver fine art print, or a beautifully done platinum print, they seem to have virtually 
unlimited scale, that you can fall right into. One of the comments people make when viewing a great platinum print is that 
there seems to be an infinity of grays, even between close tones.
When I put my lovingly made quad prints down next to them, they don't give the same impression.
By themselves, they seem to approach it, but next to a great "analogue" print, not quite there.
Sorry.
I don't know if this is illusion. I don't know if it has anything to do with how many grays the two processes can put on paper. 
I do know that I would certainly want a system that can produce for more grays than I can perceive, for a start.
Music reproduction systems that have frequency ranges beyond our hearing ability still "seem" to sound better than those 
strictly limited to our hearing limits. The same thing may apply here.
I'm sorry this has bored people or seem irrelevant. But any possible way to bring the true feel of a great photographic print 
to the Epson, whether it be file prep, materials, or highly technical issues about software/hardware are certainly of 
immense interest to me.
I think this list is called "DigitalBlackandWhiteThePrint".
Tyler

Roy,

> It's really amazing how
> many people are fixated on a digital, discrete input file
> producing a print
> composed of digital, discrete, distinguishable gray values

No one here has EVER said that.  If you believe that is what I, or I
believe, anyone else here believes, you are mistaken.

> and how many
> of those tones there are.

How many tones there are IS important to understand, if you want to
understand how to control the input to the driver to get your desired
output...if you care.

> The whole marketing point of the Piezo 1000 gray value claim is that it
> way higher than humanly discernable so you are assured of being able
> to have a smooth transition between any tonal values.

Perhaps, but that's not the claim.  If the claim was 200 tones, I'd buy
that...but 1000 is simply not possible, as far as I can tell.

Regards,

Austin

Keith

If ever you are successful in convincing manufacturers to limit the quality
of their output to what you can see, please make sure that you can see at
least as well as I first.

Todd

> 
> 
> Carolyn Frayn wrote:
> 
>>> Come on folks, you all knew this was a dynamic range conversation waiting to
>>> happen.  ;-)
>>> 
>>> 
>> 
>> 
>> Oh man Todd, you can't be that bored!
>> 
>> 
>> 
>> 
> Back to the issue of NUMBER of tones...
> 
> The baseline for measuring tones HAS to be the human eye..  Otherwise it
> doesn't make much sense, right?  I mean we could theoretically design
> color spaces that incorporate the IR and UV portions of spectra, but
> they wouldn't add a single tone the human eye could discern..
> 
> IF Cone and others are creating tones the human eye can't distinguish
> form another tone, who the HELL CARES?
> 
> PLUS, the standard FOR differences between tones is WHETHER the human
> eye can discern them as different..  Accordingly, if 4000 plus tones can
> be measured as different by a high quality spectro, BUT the human eye
> cannot differentiate them..  They simply ARE NOT 4000 different tones..
> They ARE only however many different tones the human eye could discern
> out of a 4000 swatch sample of those tones..
> 
> PS - I refuse to start making prints FOR butterflies and bumblebees...
> The ubiquitous and smarmy prints OF butterflies and bumblebees
> throughout the interiors and furnishing market are bad enough..  ;-)
> Keith

Keith:

>> IF Cone and others are creating tones the human eye can't distinguish
>> form another tone, who the HELL CARES?


Tyler writes:

> I do.
of course you do. So do I.

> When I put my lovingly made quad prints down next to them, they don't give the
> same impression.
> By themselves, they seem to approach it, but next to a great "analogue" print,
> not quite there.

Your prints don't need to be compared to anything. They stand on their own
as an exemplary body of work and a perfect example of what someone with
talent, knowledge and understanding can do with inkjet technology.

> Sorry.
> I don't know if this is illusion. I don't know if it has anything to do with
> how many grays the two processes can put on paper.
> I do know that I would certainly want a system that can produce for more grays
> than I can perceive, for a start.
> Music reproduction systems that have frequency ranges beyond our hearing
> ability still "seem" to sound better than those
> strictly limited to our hearing limits. The same thing may apply here.

Isn't all this based on science yet to be disproven.  I'm curious how anyone
can say for certain how many tones, how many whatever, the human species can
determine.  Science hick that I am.

> I'm sorry this has bored people or seem irrelevant.

Only those with the largest opinions of themselves.

> But any possible way to
> bring the true feel of a great photographic print
> to the Epson, whether it be file prep, materials, or highly technical issues
> about software/hardware are certainly of
> immense interest to me.

As I thought it was to those on the rest of this list.

> I think this list is called "DigitalBlackandWhiteThePrint".
> Tyler

Lately I believe it is called the "my opinion is the only one that matters"
show.

Carolyn

Todd Flashner wrote:

>Keith
>
>If ever you are successful in convincing manufacturers to limit the quality
>of their output to what you can see, please make sure that you can see at
>least as well as I first.
>
>Todd
>
>  
>
How about what the "best traditional printers" can see.. LOL

You must have been in this month's print exchange and hate my prints.. LOL


Keith
 



[Non-text portions of this message have been removed]

Roy,

> Well I don't feel quite so bad, Jon Cone gave you the same answer as I
> did and again you missed it.

No, Roy, I did not miss "it".  What you and Jon said, I knew long before you
two said it.  What's interesting is that you both are not answering my
questions.  You are off on a tangent that people already understand and is
not in dispute.  Yes, the output does not match the input 1:1, and YES it is
THEORETICALLY possible to produce INFINITE tones with only 1 ink, and I've
said this way early in the discussion.  That all doesn't mean that the Piezo
does in fact print 1000 tones though.

> The only place that contains "1000 gray values"
> is the print.  What can that possibly mean?  You use a densitometer of
> sufficient quality and look for different values.  As you go over
> the whole
> print if you can come up with 1000 different density numbers then the
> "1000 gray values" criteria has been satisfied.

And that is what I simply don't believe...that there are 1000 different
density values on a print, that are intentionally printed by the Piezo
software/ink combination etc.  I don't believe it's been measured as such
either.  If it has, then so be it...but until someone actually says they
have done it, and they have physically identified 1000 different tones, I
simply do not believe it is possible from Piezo.

> So, is this at
> all possible
> given an 8-bit input file?  Sure, it's quite easy.

Theoretically it is possible, but practically it is not, as far as I am
concerned.

> All you need is the
> densitometer to be reading an area that is (as you say) derived from
> 4 pixels of the original file.   In going from a value 102 to a value 103,
> by averaging 4 pixels you can get 102, 102.25, 102.5, 102.75, 103.
> This gives you 4 gray values for each input pixel level so
> 4*256 = 1024 gray values.

I know what you are saying, but I simply do not believe it is capable of
working that way.  I don't believe you know exactly how many tones Piezo
prints and how it prints them, you're speculating...but you're also giving
examples that have already been discussed, and don't answer the real
questions.  I'm not saying you're wrong...but it is still speculation...

I'll repeat it here as simply as I can, so you don't misunderstand
this...again.  I understand that there is not a 1:1 input vs output with
dithered printing...as I've written many dither algorithms and designed
dithering hardware.  I completely understand how dithering works.  I
understand that theoretically you can get 1000 tones from a dithered
printing system...given enough area, small enough dot sizes, and enough
different tones of ink...and/or combinations of these.  I understand all
that, and have always throughout this conversation understood that.

What I don't believe is that the system is actually practically capable of
it.  Plain and simple.  Any amount of speculation as to HOW it does it
doesn't answer the question.  Showing a print that shows 1000 discernable
tones...like 1000 1/2"x1/2" blocks...not simply a gradient, that will mask
the systems abilities, since you will not be measuring individual tones, but
multiple tones at once, therefore giving you the impression of it producing
more tones than it does.

Austin

tboleyyh wrote:

>--- In DigitalBlackandWhiteThePrint@y..., "Editor P.O.V. Image Service" <editor@p...> wrote:
>snip
>  
>
>>IF Cone and others are creating tones the human eye can't distinguish 
>>from another tone, who the HELL CARES?
>>    
>>
>
>I do.
>Well done B&W inkjet prints look great, I've certainly committed to pursuing this form of reproduction for my work.
>But,
>When I look at a masterfully created silver fine art print, or a beautifully done platinum print, they seem to have virtually 
>unlimited scale, that you can fall right into. One of the comments people make when viewing a great platinum print is that 
>there seems to be an infinity of grays, even between close tones.
>When I put my lovingly made quad prints down next to them, they don't give the same impression.
>By themselves, they seem to approach it, but next to a great "analogue" print, not quite there.
>Sorry.
>I don't know if this is illusion. I don't know if it has anything to do with how many grays the two processes can put on paper. 
>I do know that I would certainly want a system that can produce for more grays than I can perceive, for a start.
>Music reproduction systems that have frequency ranges beyond our hearing ability still "seem" to sound better than those 
>strictly limited to our hearing limits. The same thing may apply here.
>I'm sorry this has bored people or seem irrelevant. But any possible way to bring the true feel of a great photographic print 
>to the Epson, whether it be file prep, materials, or highly technical issues about software/hardware are certainly of 
>immense interest to me.
>I think this list is called "DigitalBlackandWhiteThePrint".
>
>  
>
I'm not talking about the final output.. of course if you can notice a 
difference, then that means axiomatically THAT YOU  MUST be able to 
distinguish  the tones..

The example you posit of sound systems (MP3 and CDs being the obvious 
inference) where you cannot "hear" certain tones is faulty and likely a 
result of having bought into what the PR says..  The fact is that the 
tones they leave out of the compressed versions of these files ARE 
individually perceptibel, but, in the vast majority of listeners, no 
appreciable difference is noted when they are removed IF those tones 
occur simultaneowuly with certain other tones..  That's a problem of 
processing in the brain, not the simple ability to perceive the sounds.. 
(In many cases it may also reflect the inadequacy not of the listenter 
but of the equipment used for the repro)

I agree with you wholeheartedly that I prefer the sound of  full 
spectrum stereo reproduction audio.. BUT, that is only superficially 
analogous to the color/tone issue and the way you present it is 
certainly NOT analogous..

Surely, piezo prints may be ineffably better than a similar print with 
the same or  similar inks and another driver...  BUT, simply because we 
can't immediately SEE why  print A is better than print B, does not make 
the explanation of oodles of tones the human eye cannot see any more 
acceptable..

Now, that said, we need to differentiate between being able to discern 
tonal differences when tones are presented in close proximity and those 
presented in the absolute..  The fact is, in a smooth transition, tonal 
differences between different swatches may be blurred perceptively (i.e. 
we  may not pick the right points where tones actually do shift 
perceptibly).. I would differentitate that from the aboslute of being 
"unable to perceive" a specific tone as being different from other 
similarly toned targets..

BTW: I never implied the topic was boring.. It's not.. But if you 
cannot, in the absolute sense, perceive a tonal difference it may 
actually be counterproductive in that you design something to print to a 
tone the human eye does EVER perceive and invite problems in more 
crossovers, etc..



Keith
 
 



[Non-text portions of this message have been removed]

Keith wrote:
> I'm not talking about the final output..

that is exactly what the original discussion was about for crying out loud.


> 
> The example you posit of sound systems (MP3 and CDs being the obvious
> inference) where you cannot "hear" certain tones is faulty and likely a
> result of having bought into what the PR says..

oh that's priceless... just priceless.

I didn't read past that one.

Carolyn

>>Lately I believe it is called the "my opinion is the only one that
matters" show.<<

... along with the "special" daily sneak preview of the upcoming smash hit
musical "I said that you said that I said you might have said... but it
doesn't really matter because I am not listening to you anyway."

;)

----- Original Message -----

From: "tboleyyh" <tyler@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, August 05, 2002 12:32 PM
Subject: [Digital BW] Number of tones was Re: Do inkjets dither or not?


> --- In DigitalBlackandWhiteThePrint@y..., "Editor P.O.V. Image Service"
<editor@p...> wrote:
> snip
> > IF Cone and others are creating tones the human eye can't distinguish
> > form another tone, who the HELL CARES?
>
> I do.

Tyler,

Me too.

> Well done B&W inkjet prints look great, I've certainly committed to
pursuing this form of reproduction for my work.
> But,
> When I look at a masterfully created silver fine art print, or a
beautifully done platinum print, they seem to have virtually
> unlimited scale, that you can fall right into. One of the comments people
make when viewing a great platinum print is that
> there seems to be an infinity of grays, even between close tones.
> When I put my lovingly made quad prints down next to them, they don't give
the same impression.
> By themselves, they seem to approach it, but next to a great "analogue"
print, not quite there.
> Sorry.

For what? You are one of the most meticulous workers around. I think it just
a matter of different mediums. Oil paint vs. acrylic paint type of thing.
Judge each print on its own merits.

Having said that, <G> how much of a role do you think that chromatic
complexity plays into the comparison?

> I don't know if this is illusion. I don't know if it has anything to do
with how many grays the two processes can put on paper.
> I do know that I would certainly want a system that can produce for more
grays than I can perceive, for a start.
> Music reproduction systems that have frequency ranges beyond our hearing
ability still "seem" to sound better than those
> strictly limited to our hearing limits. The same thing may apply here.

Good analogy. If we did some experiment to find out what the minimum density
change is that the human eye can detect and processed our files accordingly
I don't think we would not get very pleasing results. Assume it is
equivalent to 100 levels and the biggest difference we can see is a unit of
1. Well we don't want to see just the difference between 2 and 3 or 65 and
66, we want to be able to see the difference between 2.2 and 3.2 and 65.6
and 66.6. To do that we would need 1000 levels whether we can distinguish
between two adjacent levels or not.

This comes back to the idea of distinguishable pairs. We can't just take the
range and divide it by the smallest difference we can see and say that is
the total number of levels we need. We need to determine what is the number
of distinguishable pairs needed to give us a tonally rich and continuous
tone print.

> I'm sorry this has bored people or seem irrelevant. But any possible way
to bring the true feel of a great photographic print
> to the Epson, whether it be file prep, materials, or highly technical
issues about software/hardware are certainly of
> immense interest to me.

Same here and while we can really get bogged down in these discussions they
often help me form new ideas or confirm old ones.

> I think this list is called "DigitalBlackandWhiteThePrint".

Yeah I am afraid so and it is my fault, although I did have some help from
Yahoo.

Martin

> 
>>> Lately I believe it is called the "my opinion is the only one that
> matters" show.<<
> 
> ... along with the "special" daily sneak preview of the upcoming smash hit
> musical "I said that you said that I said you might have said... but it
> doesn't really matter because I am not listening to you anyway."
> 
> ;)

oh, I like that one.

Carolyn

> Todd Flashner wrote:
> 
>> Keith
>> 
>> If ever you are successful in convincing manufacturers to limit the quality
>> of their output to what you can see, please make sure that you can see at
>> least as well as I first.
>> 
>> Todd
>> 

The editor wrote:

> How about what the "best traditional printers" can see.. LOL
> 
> You must have been in this month's print exchange and hate my prints.. LOL
> 
> 
> Keith


Funny, I read what Todd wrote with sincere agreement.  What would the
thoughts of others regarding your prints in a print exchange have to do with
anything you are incessantly and inflatingly opining.

Carolyn

----- Original Message -----

From: "Carolyn Frayn" <carolynfrayn@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, August 05, 2002 1:29 PM
Subject: Re: [Digital BW] Number of tones was Re: Do inkjets dither or not?


(big snip)
>
> Isn't all this based on science yet to be disproven.  I'm curious how
anyone
> can say for certain how many tones, how many whatever, the human species
can
> determine.  Science hick that I am.

I believe that there have been studies done to determine how many tones a
person can see or what is the minimum density difference that can be
detected. I have heard result ranging from 100 to 1000+ and not enough
information was given about the trials to draw any conclusion.

One thing that is certain is that is varies from person to person. It is not
going to be a fixed value for everyone. On top of that it is going to vary
with each individual depending upon the situation. We all know that when we
move from extremes of light our irises expand or contract to adjust. In
addition the rods and cones in the retina also undergo adjustments. They can
also become fatigued or over saturated with a single color and adjust to
compensate. Ultimately it is not just our eyes but our brains as well. I
think that you have to look at the entire process of visual perception
including how our brain compensates and adjusts for the visual information
coming form the eyes.

(snip)

> > I think this list is called "DigitalBlackandWhiteThePrint".
> > Tyler
>
> Lately I believe it is called the "my opinion is the only one that
matters"
> show.
>
Yahoo won't let me use spaces so that would really run together. <G>

Martin

Martin Wesley wrote:

>-
>
>This comes back to the idea of distinguishable pairs. We can't just take the
>range and divide it by the smallest difference we can see and say that is
>the total number of levels we need. We need to determine what is the number
>of distinguishable pairs needed to give us a tonally rich and continuous
>tone print.
>
>  
>
Certainly...

Of course, we will come up with different numbers for differing 
combinations of ink, media, lighting., etc... I think what what is clear 
so far is that:

1)    Speakers, and sometimes reporters, use terminology in imprecise 
ways to represent ideas either they or the listener imperfectly understand

2)    Marketers have ALWAYS taken advantage of the imprecision of 
language (from Pharisees, to snake oil salesmen, to Olli North, to Bill 
Clinton, to those who write TV commercials, etc..) our goal as consumers 
is to force the marketers to give more precise answers. (kudos to those 
asking Jon to be more explicit instead of using vague "smoke and 
mirrors" terminology)

2)     A lot more basic research is still to be done in this area..

3)    The playing field will keep shifting as technology gets better

4)    The bottom  line is that we all need to use the best tool we can 
to produce the best print  we (both generically and individually) can 
produce


Keith
 




[Non-text portions of this message have been removed]

Martin Wrote: 
> I believe that there have been studies done to determine how many tones a
> person can see or what is the minimum density difference that can be
> detected. I have heard result ranging from 100 to 1000+ and not enough
> information was given about the trials to draw any conclusion.

> One thing that is certain is that is varies from person to person. It is not
> going to be a fixed value for everyone. On top of that it is going to vary
> with each individual depending upon the situation. We all know that when we
> move from extremes of light our irises expand or contract to adjust. In
> addition the rods and cones in the retina also undergo adjustments. They can
> also become fatigued or over saturated with a single color and adjust to
> compensate. Ultimately it is not just our eyes but our brains as well. I
> think that you have to look at the entire process of visual perception
> including how our brain compensates and adjusts for the visual information
> coming form the eyes.

Thank you Martin. It is always a pleasure to read words of reason and
thoughtfulness. I guess that is what has been bothering me about some of
what has been written lately. I don't think what we perceive visually has
anything to do with a claim of how many tones a print has. (perception vs
fact (or a claimed fact as it were)). Add to that, there are just too many
other things involved with the very  nature of the human species, and
'scientic facts' can change over time to boot. I take exception I suppose
when people hold a position so relentlessly, sometimes clouding the original
issue into obscurity.  But hey, that's just me.


> 
> (snip)
> 
>>> I think this list is called "DigitalBlackandWhiteThePrint".
>>> Tyler
>> 
>> Lately I believe it is called the "my opinion is the only one that
>> matters"
>> show.
>> 
> Yahoo won't let me use spaces so that would really run together. <G>

Might be fun though, but ya... you're right ;-)

Carolyn

Carolyn Frayn wrote:

>
>Funny, I read what Todd wrote with sincere agreement.  What would the
>thoughts of others regarding your prints in a print exchange have to do with
>anything you are incessantly and inflatingly opining.
>
>  
>
You know what Carolyn, that's two flames in a row...

I won't respond a second time in return onlist...

However, you have been clearly trying to incite a personal battle with 
me here.. We can go back through your posts in reposte to mine and the 
tone has gotten more and more derisive..

I doubt the rest of this list wnats to hear me launch into an 
uncompromised attack upon you in return..  But, if you persist, I will 
either expect the moderator (of this moderated list) to censor you or I 
will simply  respond in kind..

That's my last warning..


Keith
 
 

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[Non-text portions of this message have been removed]

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> 
> Roy,
> 
> > Well I don't feel quite so bad, Jon Cone gave you the same answer as I
> > did and again you missed it.
> 
> No, Roy, I did not miss "it".  What you and Jon said, I knew long before you
> two said it.  What's interesting is that you both are not answering my
> questions.  

Austin,

You did write this, didn't you?
> > > > If the file only contains 256 levels of gray, and IF (BIG IF) what you claim
> > > > is true, that standard Piezo is capable of 1000 tones, where do the extra
> > > > 744 levels of gray come from? How, exactly, are they derived?

Don't Jon and I answer where the other 744 levels come from?

You are off on a tangent that people already understand and is
> not in dispute.  Yes, the output does not match the input 1:1, and YES it is
> THEORETICALLY possible to produce INFINITE tones with only 1 ink, and I've
> said this way early in the discussion.  That all doesn't mean that the Piezo
> does in fact print 1000 tones though.

Jon's Piezo website claims this.  I make no claim whether or not it actually
does this, because I don't know.  I only claim that your argument of 8-bit can't
make 1000 levels is flawed.

> 
> > The only place that contains "1000 gray values"
> > is the print.  What can that possibly mean?  You use a densitometer of
> > sufficient quality and look for different values.  As you go over
> > the whole
> > print if you can come up with 1000 different density numbers then the
> > "1000 gray values" criteria has been satisfied.
> 
> And that is what I simply don't believe...that there are 1000 different
> density values on a print, that are intentionally printed by the Piezo
> software/ink combination etc.  I don't believe it's been measured as such
> either.  If it has, then so be it...but until someone actually says they
> have done it, and they have physically identified 1000 different tones, I
> simply do not believe it is possible from Piezo.

I'm fine that you don't believe the Piezo claim.  The problem is you can't
PROVE it false mathematically.

> 
> > So, is this at
> > all possible
> > given an 8-bit input file?  Sure, it's quite easy.
> 
> Theoretically it is possible, but practically it is not, as far as I am
> concerned.
> 
> > All you need is the
> > densitometer to be reading an area that is (as you say) derived from
> > 4 pixels of the original file.   In going from a value 102 to a value 103,
> > by averaging 4 pixels you can get 102, 102.25, 102.5, 102.75, 103.
> > This gives you 4 gray values for each input pixel level so
> > 4*256 = 1024 gray values.
> 
> I know what you are saying, but I simply do not believe it is capable of
> working that way.  I don't believe you know exactly how many tones Piezo
> prints and how it prints them, you're speculating...but you're also giving
> examples that have already been discussed, and don't answer the real
> questions.  I'm not saying you're wrong...but it is still speculation...

All either one of us can do is speculate, neither of us KNOWS whether
or not piezo can or cannot print that many grays.  The math of the
situation PROVES neither side.

The only info we really have is that the Piezo website claims 1000 grays.
Maybe Cone has measured them all, maybe he hasn't.  Maybe he calculated
it theoretically, maybe not.  Maybe it just marketing hype, maybe not.
Maybe he'd tell us which, maybe not.  Maybe we should care, maybe not.

> 
> I'll repeat it here as simply as I can, so you don't misunderstand
> this...again.  I understand that there is not a 1:1 input vs output with
> dithered printing...as I've written many dither algorithms and designed
> dithering hardware.  I completely understand how dithering works.  I
> understand that theoretically you can get 1000 tones from a dithered
> printing system...given enough area, small enough dot sizes, and enough
> different tones of ink...and/or combinations of these.  I understand all
> that, and have always throughout this conversation understood that.
> 
> What I don't believe is that the system is actually practically capable of
> it.  Plain and simple.  Any amount of speculation as to HOW it does it
> doesn't answer the question.  

"HOW it may do it" doesn't prove that it does, but it does disprove the
argument that it's impossible.

Showing a print that shows 1000 discernable
> tones...like 1000 1/2"x1/2" blocks...not simply a gradient, that will mask
> the systems abilities, since you will not be measuring individual tones, but
> multiple tones at once, therefore giving you the impression of it producing
> more tones than it does.
> 
> Austin

Roy

BTW, a little aside:  I noticed on the piezo website that the claim of
2160 dpi is now qualified by the word "effectively" -- a nice addition.

Roy

Roy,

> Austin,
>
> You did write this, didn't you?
> > > > > If the file only contains 256 levels of gray, and IF (BIG
> IF) what you claim
> > > > > is true, that standard Piezo is capable of 1000 tones,
> where do the extra
> > > > > 744 levels of gray come from? How, exactly, are they derived?
>
> Don't Jon and I answer where the other 744 levels come from?

No, neither of you did.  You speculated, and Jon simply didn't answer it.  I
understand how they CAN be derived, but not how they ARE derived.

> You are off on a tangent that people already understand and is
> > not in dispute.  Yes, the output does not match the input 1:1,
> and YES it is
> > THEORETICALLY possible to produce INFINITE tones with only 1
> ink, and I've
> > said this way early in the discussion.  That all doesn't mean
> that the Piezo
> > does in fact print 1000 tones though.
>
> Jon's Piezo website claims this.  I make no claim whether or not
> it actually
> does this, because I don't know.  I only claim that your argument
> of 8-bit can't
> make 1000 levels is flawed.

I never said it CAN'T make 1000 theoretically...just that I doubt it
actually DOES in reality.  What's flawed?  Where is the flaw?  Precisely...
Don't simply say something is flawed, and not say what about it is flawed.
I've been VERY precise with my disbelief in the 1000 tone claim, citing
reasons why I believe the physical hardware and inks don't do it.

> The problem is you can't
> PROVE it false mathematically.

I CAN PROVE it mathematically.  I've ALWAYS said that, and completely
understand how it THEORETICALLY can be done.  And, as I've said, you don't
need four inks to do so.  That merely reduces the area you need to do it.

> All either one of us can do is speculate

Not so.  I can ask to see an example that shows 1000 tones.  That's not
speculation at all.  I simply don't want to speculate, I want to know if the
claim is true or not.  Not mumbo jumbo theoretical fluff.  This is reality.
Does there exist a print that was printed with Piezo that has 1000 distinct
tones.  Can I print a 1000 tone step wedge and discern all 1000 tones.
Simple question.  Tyler was kind enough to give me a 256 step wedge.  I will
print it, and chart the results.  If I can't measure 256 distinct tones with
my X-Rite 810, then I am even more skeptical that it can print 1000.

> The only info we really have is that the Piezo website claims 1000 grays.
> Maybe Cone has measured them all, maybe he hasn't.  Maybe he calculated
> it theoretically, maybe not.  Maybe it just marketing hype, maybe not.
> Maybe he'd tell us which, maybe not.  Maybe we should care, maybe not.

And claims should be backed up with some substantiation...that's all I ask.

> "HOW it may do it" doesn't prove that it does, but it does disprove the
> argument that it's impossible.

There is a VAST difference between things being theoretically "shown to
work" on paper, and working in reality.  If you are a scientist or an
engineer, you should certainly understand that...if you've ever had to
actually make something work.  Something MAY look good on paper, but
completely fail in reality.  So, because I know it is theoretically possible
does not prove that it's not impossible.

> BTW, a little aside:  I noticed on the piezo website that the claim of
> 2160 dpi is now qualified by the word "effectively" -- a nice addition.

And that is an issue that I've had too, as the physical hardware can simply
not do that, as far as I can tell from the service manual and the Epson
programming documentation I have access to.  The printer is only hardware
capable of 1440...and Jon made a claim that there are more commands that the
printer has than the ones published...and I believe that...but whether any
of them actually allow you to get around the physical hardware limitation is
still left unexplained...

Regards,

Austin

However, quantization to 8 bits carries only a fixed amount of 
information and has a fixed noise floor. What you can do is limited by 
that. See any good text on information theory or if  you need source 
from imaging see any good reference on imaging radar.

Truman

royvharrington wrote:

>
>
> Jon's Piezo website claims this.  I make no claim whether or not it 
> actually
> does this, because I don't know.  I only claim that your argument of 
> 8-bit can't
> make 1000 levels is flawed.
>

<snip>
I simply don't want to speculate, I want to know if the claim is true 
or not. Not mumbo jumbo theoretical fluff.....<snip>

blah, blah, blah, blah, blah.....

Boring!

JC

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> Roy,
> 

> > I only claim that your argument
> > of 8-bit can't
> > make 1000 levels is flawed.
> 
> I never said it CAN'T make 1000 theoretically...just that I doubt it
> actually DOES in reality.  What's flawed?  Where is the flaw?  Precisely...
> Don't simply say something is flawed, and not say what about it is flawed.
> I've been VERY precise with my disbelief in the 1000 tone claim, citing
> reasons why I believe the physical hardware and inks don't do it.

The only reason I've seen is: 2^8 = 256 < 1000.

> 
> > The problem is you can't
> > PROVE it false mathematically.
> 
> I CAN PROVE it mathematically.

Did you leave out the word "false" intentionally?

  I've ALWAYS said that, and completely
> understand how it THEORETICALLY can be done.  And, as I've said, you don't
> need four inks to do so.  That merely reduces the area you need to do it.
> 
> > All either one of us can do is speculate
> 
> Not so.  I can ask to see an example that shows 1000 tones.  That's not
> speculation at all.  I simply don't want to speculate, I want to know if the
> claim is true or not.

Why don't you ask Jon Cone if the claim is true or not.   
Realistically, I've never seen marketing material backed up with lots of 
absolute proof, examples, and test procedures.

  Not mumbo jumbo theoretical fluff.  This is reality.
> Does there exist a print that was printed with Piezo that has 1000 distinct
> tones.  Can I print a 1000 tone step wedge and discern all 1000 tones.
> Simple question.  Tyler was kind enough to give me a 256 step wedge.  I will
> print it, and chart the results.  If I can't measure 256 distinct tones with
> my X-Rite 810, then I am even more skeptical that it can print 1000.

I wish you luck in this try, but I wonder if you've thought this out.  As far as
I can tell from the online spec sheet of the X-Rite 810, it reads in 0.01D units.
Since the dmax you're likely to get is less than 2.00D the number of distinct
readouts from your X-Rite has to be less than 200.  So I'm quite sure you'll
get less than 256 distinct measurements regardless of whatever the piezo
system prints.  Also, did you consider the area of measurement for the
X-Rite?  The spec says 4mm so I'll assume that really means 4mm^2.
At a mere 300ppi = 12ppmm input file, we've got 4*12*12 = 576 pixels
of the original file under that densitometer.  That's quite a large sampling
average.  BTW, a 256 step wedge comes right on the piezo software
CD -- that's what I used for the exact same test a couple of days ago.


> 
> > BTW, a little aside:  I noticed on the piezo website that the claim of
> > 2160 dpi is now qualified by the word "effectively" -- a nice addition.
> 
> And that is an issue that I've had too, as the physical hardware can simply
> not do that, as far as I can tell from the service manual and the Epson
> programming documentation I have access to.  The printer is only hardware
> capable of 1440...and Jon made a claim that there are more commands that the
> printer has than the ones published...and I believe that...but whether any
> of them actually allow you to get around the physical hardware limitation is
> still left unexplained...

Geez, Austin, the word "effectively" nullifies Jon's original claim.  It no
longer says it prints "at 2160 dpi" which several of us rightly thought
was physically impossible.  The current quote is "effective resolution of
2160 dpi" which is sufficiently vague as to not really claim anything.

The point is you WON that argument, we all won that argument.

> 
> Regards,
> 
> Austin

Roy

--- In DigitalBlackandWhiteThePrint@y..., "Martin Wesley" <mwesley250@e...> wrote:
snip
> > By themselves, they seem to approach it, but next to a great "analogue"
> print, not quite there.

>...how much of a role do you think that chromatic
> complexity plays into the comparison?
Probably something, I certainly prefer it as we've discussed. On the other hand older Frank Gohlke's prints that I've seen 
are extremely monochromatic, and not very dramatic in contrast, yet they have that infinite continuous tone quality.
Resolution probably has something to do with it as well, some of the traditional prints that convey this best are contact 
prints.
You are right that it is a different print medium with it's own qualities, but this one trade-off seems hard to swallow 
sometimes. It's one quality unique to photography.

> > I'm sorry this has bored people or seem irrelevant. But any possible way
> to bring the true feel of a great photographic print
> > to the Epson, whether it be file prep, materials, or highly technical
> issues about software/hardware are certainly of
> > immense interest to me.
> 
> Same here and while we can really get bogged down in these discussions they
> often help me form new ideas or confirm old ones.
I've certainly been bored to tears with some threads that others find valuable, so I guess we all have to be tolerant. There 
are a wide range of interests.
Tyler

--- In DigitalBlackandWhiteThePrint@y..., Carolyn Frayn <carolynfrayn@s...> wrote:
snip
> Your prints don't need to be compared to anything. They stand on their own
> as an exemplary body of work and a perfect example of what someone with
> talent, knowledge and understanding can do with inkjet technology.

If you recall I didn't let you look at any one of them for more than about 15 seconds.
That's the key.
Shorter is even better if you can get away with it.
Tyler

> > > I only claim that your argument
> > > of 8-bit can't
> > > make 1000 levels is flawed.
> >
> > I never said it CAN'T make 1000 theoretically...just that I doubt it
> > actually DOES in reality.  What's flawed?  Where is the flaw?
> Precisely...
> > Don't simply say something is flawed, and not say what about it
> is flawed.
> > I've been VERY precise with my disbelief in the 1000 tone claim, citing
> > reasons why I believe the physical hardware and inks don't do it.
>
> The only reason I've seen is: 2^8 = 256 < 1000.

Roy,

The only reason for what you've seen?  I've given technical and practical
reasons why I don't believe the Pizeo system really prints "over 1000"
tones...have you simply ignored them?

> >
> > > The problem is you can't
> > > PROVE it false mathematically.
> >
> > I CAN PROVE it mathematically.
>
> Did you leave out the word "false" intentionally?

No, what I said is exactly what I mean.  I CAN prove I can THEORETICALLY
print an infinite number of tones with only a single ink, much less four,
given enough print area, and a large enough viewing distance.  But...simply
because it looks good on paper does not mean it will work in reality, at
least in the Piezo case.

> Why don't you ask Jon Cone if the claim is true or not.
> Realistically, I've never seen marketing material backed up with lots of
> absolute proof, examples, and test procedures.

I have, and I so far, have not gotten, what I would consider, a straight
answer to the questions I've asked.

>   Not mumbo jumbo theoretical fluff.  This is reality.
> > Does there exist a print that was printed with Piezo that has
> 1000 distinct
> > tones.  Can I print a 1000 tone step wedge and discern all 1000 tones.
> > Simple question.  Tyler was kind enough to give me a 256 step
> wedge.  I will
> > print it, and chart the results.  If I can't measure 256
> distinct tones with
> > my X-Rite 810, then I am even more skeptical that it can print 1000.
>
> I wish you luck in this try, but I wonder if you've thought this
> out.

Yes, of course.  I know how to conduct experiments correctly, being that
I've been doing so for over 25 years.

> As far as
> I can tell from the online spec sheet of the X-Rite 810, it reads
> in 0.01D units.
> Since the dmax you're likely to get is less than 2.00D the number
> of distinct
> readouts from your X-Rite has to be less than 200.  So I'm quite
> sure you'll
> get less than 256 distinct measurements regardless of whatever the piezo
> system prints.

I understand that.  If I get even near the max of the unit, that's more than
I was expecting, and I will simply move on to a higher resolution unit.  The
X-Rite is only a starting point.

> Also, did you consider the area of measurement for the
> X-Rite?

Yes, the pattern is much bigger than is required.  We're talking 256 patches
on an 8.5 x 11 sheet.  That would give a possible area of (25.4 x 8.5) x
(25.4 x 11) / 256 or ~235 sq mm per patch, and the X-Rite measuring area is
4mm (which, BTW, I believe means 4mm of area, as in a circle with an area of
4mm...).

> BTW, a 256 step wedge comes right on the piezo software
> CD -- that's what I used for the exact same test a couple of days ago.

Is the flush image a 256 step wedge?  The others certainly aren't...  I
thought you said you measured a gradient?

In fact, if the flush image is in fact a 256 step wedge, it may be better
suited to what I'm trying to see...as the "Z" pattern is more for visual
discernability, than for densitometer measurement...as the "Z" is in the
middle of the patch.

Regards,

Austin

Some interesting links dealing with the number of graytones the human eye
can discern:

This one says 64:

http://orbit-net.nesdis.noaa.gov/arad/fpdt/tutorial/enhance.html

This one says 200 (and is a great primer on the halftone process):

http://www.adobe.com/support/techguides/printpublishing/scanning/psscanning0
2.html

And this one says between 30 and 65...but up to 80 on a monitor:

http://www.fortunecity.com/victorian/canterbury/222/astrovid6.htm

And this one even has publication references...and states 100:1:

http://www.njit.edu/Publications/Reports/HINT/CHAPTER4.html

And I quote:

"The sensation of lightness can distinguish luminance levels within about a
two-decade range, i.e. the eye is able to resolve a luminance variation (dL)
up to about 1/100 increment [Gonzalez and Woods, 1991, p. 34]. The luminance
discrimination threshold depends on the individual subject and the dark
adaptation of the eye during the test. Human vision adapts over a remarkably
large range of light intensity levels - about seven decades of dynamic range
in total [Billmeyer and Saltzman, 1981]. At each adaptation state the human
eye can discern a dynamic range as high as 100:1."

Austin

> > BTW, a 256 step wedge comes right on the piezo software
> > CD -- that's what I used for the exact same test a couple of days ago.
> 
> Is the flush image a 256 step wedge?  The others certainly aren't...  I
> thought you said you measured a gradient?

The 21step file (both Piezo's and Paul Roark's) have steps on the bottom
but the top is just a gradient.  If you want a particular layout, PS can
do it very easily (the dithering in the gradient can be enabled or disabled).

Roy

> 
> In fact, if the flush image is in fact a 256 step wedge, it may be better
> suited to what I'm trying to see...as the "Z" pattern is more for visual
> discernability, than for densitometer measurement...as the "Z" is in the
> middle of the patch.
> 
> Regards,
> 
> Austin

> > > BTW, a 256 step wedge comes right on the piezo software
> > > CD -- that's what I used for the exact same test a couple of days ago.
> >
> > Is the flush image a 256 step wedge?  The others certainly aren't...  I
> > thought you said you measured a gradient?
>
> The 21step file (both Piezo's and Paul Roark's) have steps on the bottom
> but the top is just a gradient.

That is the one I thought you were using when you did your measurements
(21step)...but that's not a 256 step wedge.  What's the 256 step wedge you
are referring to?

BTW, do Rourke's "curves" print "more than 1000 tones" also?  Here is Jon's
response...of course, it doesn't answer the question...

"So if it could not and the smoothing was a bit choppy and the transitions
between tones was coarse and the eye could see all the breaks between the
overlapping inks and stuff like that - would you then say that PiezoBW looks
bad and it would need more tones to overcome those bits, and we would be on
the other side of the sun in a parallel universe doing the exact same thing
but just not as good and having a different discussion as to why we don't
use more tones than 256 so that the screening is not apparent, and the
overlapping inks is not noticeable, and that scaling is improved, and that
vignettes and blends are not blemished with digital artifacts and....... ;)"

Sigh.  I don't believe you need 1000 tones to do any of this...that under
200 would be perfectly enough.  That's why I'm curious what Rourke's curves
do...as people say they can see absolutely no difference in the same image
printed with Rourke's curves and Piezo, except Rourke's curves give a darker
black if I remember right...  I think you see where I'm going.

Austin

> Sigh.  I don't believe you need 1000 tones to do any of this...that under
> 200 would be perfectly enough.  That's why I'm curious what Rourke's curves
> do...as people say they can see absolutely no difference in the same image
> printed with Rourke's curves and Piezo, except Rourke's curves give a darker
> black if I remember right...  I think you see where I'm going.

Austin

My sense is that Roark's curves, in general, give Piezo "comparable"
quality. But remember, they are hand rolled, so it's possible that those for
some printers are better than others, and some hues (variable tone inksets)
better than others. Some of the Tyler's Zees I've printed with Roark's
curves look as good as yours done with Piezo, a couple perhaps a hair
better, and some worse. On the whole, "somewhat comparable".

My point is it's not the kind of thing where you'll get a radically
different number of tones with one set over the other. To go where you are
going with this (extended blacks) you'd be looking a the Piezo driver with
PiezoTones. They offer a higher dmax.

BTW, did anyone print Tyler's Zees with the PiezoTones? I did but not with
the Piezo driver. I'm curious if they were they able to maintain linearity
in the dark end while increasing dmax without having to create new profiles.

Todd

> 
> That is the one I thought you were using when you did your measurements
> (21step)...but that's not a 256 step wedge.  What's the 256 step wedge you
> are referring to?

Well a gradient in 8-bit is just the same as a 256 step wedge.  It not labeled
as such but it does have all 256 levels (some do appear to be doubled) and
far as I can tell there's no dithering between levels.

> 
> BTW, do Rourke's "curves" print "more than 1000 tones" also?  

No real idea, but it is a more difficult question because there are so many
different curves and they were all hand done and were somewhat limited
by the max number of points in a PS curves.

Here is Jon's
> response...of course, it doesn't answer the question...
> 
> "So if it could not and the smoothing was a bit choppy and the transitions
> between tones was coarse and the eye could see all the breaks between the
> overlapping inks and stuff like that - would you then say that PiezoBW looks
> bad and it would need more tones to overcome those bits, and we would be on
> the other side of the sun in a parallel universe doing the exact same thing
> but just not as good and having a different discussion as to why we don't
> use more tones than 256 so that the screening is not apparent, and the
> overlapping inks is not noticeable, and that scaling is improved, and that
> vignettes and blends are not blemished with digital artifacts and....... ;)"
> 
> Sigh.  I don't believe you need 1000 tones to do any of this...that under
> 200 would be perfectly enough.  

Well I suspect that 200 would be just barely enough and would have to be
perfectly placed to be good enough.   Let's say that 100 tones are humanly
discernable.  Seems to me that you need at least one more tone between
each pair.  If two tones are discernable then a gradient from one to the
other will have a posterized noticible transition.  With a tone in between
you can smoothly go from one to the middle and then from the middle to
the other tone.

That's why I'm curious what Rourke's curves
> do...as people say they can see absolutely no difference in the same image
> printed with Rourke's curves and Piezo, except Rourke's curves give a darker
> black if I remember right...  I think you see where I'm going.
> 
> Austin

Roy

Hi Roy,

> > That is the one I thought you were using when you did your measurements
> > (21step)...but that's not a 256 step wedge.  What's the 256
> step wedge you
> > are referring to?
>
> Well a gradient in 8-bit is just the same as a 256 step wedge.

Doesn't that depend on how it's made?  A step wedge typically has defined
squares...and a gradient doesn't necessarily...but it does makes sense that
it would be made that way.

I believe the flush image may be a far better data source, if it is in fact
a 256 step wedge...and since I can't get PS to display grayscale in tonal
values, it's hard to test out.  You don't happen to know how to get PS to
display the actually pixel values...not just the %, which only gives me
discernability to %1...

> It not labeled
> as such but it does have all 256 levels (some do appear to be doubled) and
> far as I can tell there's no dithering between levels.

But if there's no dithering between the levels...then doesn't that refute
the 1000 tone claim...and support the less than 256 claim?

> >
> > BTW, do Rourke's "curves" print "more than 1000 tones" also?
>
> No real idea, but it is a more difficult question because there
> are so many
> different curves and they were all hand done and were somewhat limited
> by the max number of points in a PS curves.

I'm not quite sure what PS curves have to do with it...  Isn't the data
still sent to the printer driver, which only handles 8 bits anyway...but I
guess if it is in fact printing 8 bits/channel (and in this case, it
actually is), you could theoretically get the additional tones (though it
isn't 256 x 4 BTW, since you can't print all the way to %100 with three of
the inks...and some tones would be duplicated etc....which, this argument,
in and of it self, also brings me to question Cone's claim...since you'd
have to get 512 of the tones from the black ink only etc.).

> Here is Jon's
> > response...of course, it doesn't answer the question...
> >
> > "So if it could not and the smoothing was a bit choppy and the
> transitions
> > between tones was coarse and the eye could see all the breaks
> between the
> > overlapping inks and stuff like that - would you then say that
> PiezoBW looks
> > bad and it would need more tones to overcome those bits, and we
> would be on
> > the other side of the sun in a parallel universe doing the
> exact same thing
> > but just not as good and having a different discussion as to
> why we don't
> > use more tones than 256 so that the screening is not apparent, and the
> > overlapping inks is not noticeable, and that scaling is
> improved, and that
> > vignettes and blends are not blemished with digital artifacts
> and....... ;)"
> >
> > Sigh.  I don't believe you need 1000 tones to do any of
> this...that under
> > 200 would be perfectly enough.
>
> Well I suspect that 200 would be just barely enough and would have to be
> perfectly placed to be good enough.   Let's say that 100 tones are humanly
> discernable.  Seems to me that you need at least one more tone between
> each pair.  If two tones are discernable then a gradient from one to the
> other will have a posterized noticible transition.

I understand your point.

> With a tone in between
> you can smoothly go from one to the middle and then from the middle to
> the other tone.

Well, I don't believe that in images, which is what we're talking about, the
edges of the tones are that defined, and require the transitional "over
tones", but perhaps they do to some degree.  Also, the edges are "hard"...it
was meant to be that way, and I'd rather not have intermediate tones there.
But, I understand your point...and back to my point...I believe between 100
and 200 tones would work just fine.

Regards,

Austin

> You don't happen to know how to get PS to
> display the actually pixel values...not just the %, which only gives me
> discernability to %1...

Tyler gave me the answer...use RGB mode, and it simply displays the pixel
values for all three colors...which are the same, and I assume, the same as
the grayscale value.  That seems to work.

Thanks, Tyler!

Austin

> I believe the flush image may be a far better data source, if it
> is in fact
> a 256 step wedge...

In RGB mode, it certainly appears to be...  I've printed that, and don't see
any visible transitions anywhere...in any light that I have available...
And in order to eliminate the "magic 1000 tone dithering", I've cut the
verticals in half, and compare them with tones further down until I can
visibly notice a difference...and I've got to go a tone or two down to
notice a difference.

I'm curious, can anyone else see any "transitions" or adjacent tones as
being different in the flush image (FlushPC.psd)?  I'm also curious what a
128 step wedge would visually look like...

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <
darkroom@i...> wrote:
snip
> I'm curious, can anyone else see any "transitions" or adjacent tones as
> being different in the flush image (FlushPC.psd)?  I'm also curious what a
> 128 step wedge would visually look like...
> 
> Austin

I haven't looked at the flush image, but if it is not dithered and is 
evenly spaced, you should be able to run the median filter on it, set 
right it should step at whatever intervals you want in the manner you 
are looking for.
Tyler

Hi Austin,

> Hi Roy,
> 
> > > That is the one I thought you were using when you did your measurements
> > > (21step)...but that's not a 256 step wedge.  What's the 256
> > step wedge you
> > > are referring to?
> >
> > Well a gradient in 8-bit is just the same as a 256 step wedge.
> 
> Doesn't that depend on how it's made?  A step wedge typically has defined
> squares...and a gradient doesn't necessarily...but it does makes sense that
> it would be made that way.

Yes, using the gradient tool without dithering will make squares, with dithering
it will actually smooth between transition.

> 
> I believe the flush image may be a far better data source, if it is in fact
> a 256 step wedge...and since I can't get PS to display grayscale in tonal
> values, it's hard to test out.  You don't happen to know how to get PS to
> display the actually pixel values...not just the %, which only gives me
> discernability to %1...

I see Tyler has already mentioned the RGB way to look.  Its also unfortunate
that you can never see the low bits in 16 bit mode.  The trick to see what
PS is doing is to select a smaller area and run Adjust Levels and bring the
white and black points way it.  It increases the contrast to make it easy to
see.  If you separate the W & B by a power of 2, you left shift the pixel
values by that many bits.  Recently someone mentioned that PS only uses
15 bits in high bit mode, I was able to confirm this using this method.

> 
> > It not labeled
> > as such but it does have all 256 levels (some do appear to be doubled) and
> > far as I can tell there's no dithering between levels.
> 
> But if there's no dithering between the levels...then doesn't that refute
> the 1000 tone claim...and support the less than 256 claim?

As I said above, the dithering/no-dithering gives you the steps versus
smooth transition.  I'd hope you could try both and see the results.

> 
> > >
> > > BTW, do Rourke's "curves" print "more than 1000 tones" also?
> >
> > No real idea, but it is a more difficult question because there
> > are so many
> > different curves and they were all hand done and were somewhat limited
> > by the max number of points in a PS curves.
> 
> I'm not quite sure what PS curves have to do with it...  Isn't the data

Its just that PS limits how accurate you can specify the adjustment curve.

> still sent to the printer driver, which only handles 8 bits anyway...but I
> guess if it is in fact printing 8 bits/channel (and in this case, it
> actually is), you could theoretically get the additional tones (though it
> isn't 256 x 4 BTW, since you can't print all the way to %100 with three of
> the inks...and some tones would be duplicated etc....which, this argument,
> in and of it self, also brings me to question Cone's claim...since you'd
> have to get 512 of the tones from the black ink only etc.).
> 
> 
> Well, I don't believe that in images, which is what we're talking about, the
> edges of the tones are that defined, and require the transitional "over
> tones", but perhaps they do to some degree.  Also, the edges are "hard"...it
> was meant to be that way, and I'd rather not have intermediate tones there.
> But, I understand your point...and back to my point...I believe between 100
> and 200 tones would work just fine.
> 
> Regards,
> 
> Austin

Roy

Tyler wrote:
> If you recall I didn't let you look at any one of them for more than about 15
> seconds.
It only took 10 seconds to know though..  Then there is the one on my wall,
sorry, but I looked at it longer.

> That's the key.
> Shorter is even better if you can get away with it.
No one would ever let you get away with shorter.

Carolyn

> BTW, did anyone print Tyler's Zees with the PiezoTones? I did but not with
> the Piezo driver. I'm curious if they were they able to maintain linearity
> in the dark end while increasing dmax without having to create new profiles.
> 
> Todd

I tried Todd, unfortunately that's when my piezo printer decided to take a
dive. I'll either get it running this week or buy another one, by then, if
you haven't seen or heard about the print you're curious about, I'll be glad
to send a PT-Tzzz thru the Piezo driver.

Carolyn

> I tried Todd, unfortunately that's when my piezo printer decided to take a
> dive. I'll either get it running this week or buy another one, by then, if
> you haven't seen or heard about the print you're curious about, I'll be glad
> to send a PT-Tzzz thru the Piezo driver.

Thanks C. That's way more than necessary. A verbal yes or no from someone
who's already done it is more than enough.

T

Hi Roy,

> >
> > > > That is the one I thought you were using when you did your
> measurements
> > > > (21step)...but that's not a 256 step wedge.  What's the 256
> > > step wedge you
> > > > are referring to?
> > >
> > > Well a gradient in 8-bit is just the same as a 256 step wedge.
> >
> > Doesn't that depend on how it's made?  A step wedge typically
> has defined
> > squares...and a gradient doesn't necessarily...but it does
> makes sense that
> > it would be made that way.
>
> Yes, using the gradient tool without dithering will make squares,
> with dithering
> it will actually smooth between transition.

Oh, you mean PS dithering, not Piezo driver dithering...right?

> >
> > I believe the flush image may be a far better data source, if
> it is in fact
> > a 256 step wedge...and since I can't get PS to display
> grayscale in tonal
> > values, it's hard to test out.  You don't happen to know how to
> get PS to
> > display the actually pixel values...not just the %, which only gives me
> > discernability to %1...
>
> I see Tyler has already mentioned the RGB way to look.  Its also
> unfortunate
> that you can never see the low bits in 16 bit mode.

Agreed!

> Recently someone mentioned that PS only uses
> 15 bits in high bit mode, I was able to confirm this using this method.

I've never done anything in PS in 16 bit mode, but using 15 bits is just not
kosher in my book.

> > > It not labeled
> > > as such but it does have all 256 levels (some do appear to be
> doubled) and
> > > far as I can tell there's no dithering between levels.
> >
> > But if there's no dithering between the levels...then doesn't
> that refute
> > the 1000 tone claim...and support the less than 256 claim?
>
> As I said above, the dithering/no-dithering gives you the steps versus
> smooth transition.  I'd hope you could try both and see the results.

Hum...if it's PS that's dithering...I wonder what the driver will do with it
already dithered...

> >
> > > >
> > > > BTW, do Rourke's "curves" print "more than 1000 tones" also?
> > >
> > > No real idea, but it is a more difficult question because there
> > > are so many
> > > different curves and they were all hand done and were somewhat limited
> > > by the max number of points in a PS curves.
> >
> > I'm not quite sure what PS curves have to do with it...  Isn't the data
>
> Its just that PS limits how accurate you can specify the adjustment curve.

Understood.  I still don't know how the printer driver etc. handles the
Rourke output methodology though...

> > still sent to the printer driver, which only handles 8 bits
> anyway...but I
> > guess if it is in fact printing 8 bits/channel (and in this case, it
> > actually is), you could theoretically get the additional tones
> (though it
> > isn't 256 x 4 BTW, since you can't print all the way to %100
> with three of
> > the inks...and some tones would be duplicated etc....which,
> this argument,
> > in and of it self, also brings me to question Cone's claim...since you'd
> > have to get 512 of the tones from the black ink only etc.).

What did you think of the above paragraph?

Regards,

Austin

Hi Austin,

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> 
> Hi Roy,
> 
...
> >
> > Yes, using the gradient tool without dithering will make squares,
> > with dithering
> > it will actually smooth between transition.
> 
> Oh, you mean PS dithering, not Piezo driver dithering...right?

Yes, correct. 
> 
> 
> > Recently someone mentioned that PS only uses
> > 15 bits in high bit mode, I was able to confirm this using this method.
> 
> I've never done anything in PS in 16 bit mode, but using 15 bits is just not
> kosher in my book.

I guess you weren't one the 16-bit only users.  Well 15 bits is way overkill
anyway -- the storage and work is all done with 16 bit quantities.
Computers in general use signed arithmetic so a 16 bit number actually
goes from -2^15 to +2^15-1  or -32768 to 32767.   I suspect that they
just use the positive numbers.  It would also have a very significant
performance benefit --- like 20% faster or even more.   Why?  With
every single operation on a pixel value you need to check for overflow
or underflow of the value.  Using just 15 bits means that the top bit
should always be 0, overflow or underflow would be characterized by
the top bit being a 1.  This is very easy and FAST to check.  In order
to do 16 bit unsigned arithmetic, one would actually have to perform
every operation in 32 bit mode so the over/under flow info wouldn't
be lost.

Well worth it in my opinion.

> 
> > > > It not labeled
> > > > as such but it does have all 256 levels (some do appear to be
> > doubled) and
> > > > far as I can tell there's no dithering between levels.
> > >
> > > But if there's no dithering between the levels...then doesn't
> > that refute
> > > the 1000 tone claim...and support the less than 256 claim?
> >
> > As I said above, the dithering/no-dithering gives you the steps versus
> > smooth transition.  I'd hope you could try both and see the results.
> 
> Hum...if it's PS that's dithering...I wonder what the driver will do with it
> already dithered...

There's nothing wrong with dithering upon dithering.

> 
> >
> > Its just that PS limits how accurate you can specify the adjustment curve.
> 
> Understood.  I still don't know how the printer driver etc. handles the
> Rourke output methodology though...

There's nothing particularly special about it.

> 
> > > still sent to the printer driver, which only handles 8 bits
> > anyway...but I
> > > guess if it is in fact printing 8 bits/channel (and in this case, it
> > > actually is), you could theoretically get the additional tones
> > (though it
> > > isn't 256 x 4 BTW, since you can't print all the way to %100
> > with three of
> > > the inks...and some tones would be duplicated etc....which,
> > this argument,
> > > in and of it self, also brings me to question Cone's claim...since you'd
> > > have to get 512 of the tones from the black ink only etc.).
> 
> What did you think of the above paragraph?

I not really sure I understand what's really being said or asked, but I'll
try.   It you start out with an 8 bit grayscale you have 256 possible
values.  When you convert to RGB you still have only 256 values,
likewise you adjust curves, you still have only 256 values.
Sure there's lots more bits but only 256 combinations will be used.
The 4 shades of ink doesn't increase the number of grays either.
It just makes it do a better job of getting 256 levels.  So I don't
buy any 256*4 calculation for ONE pixel.  Its the averaging of
MULTIPLE pixels that gives you more gray values -- that's the
only way you can get more grays.  Note that the averaging can
happen in many ways, explicitly in the driver, ink bleed on the
paper, limited resolution of our eyes, or measuring area of the
densitometer.   The 4 inks are a big help in making the averaging 
work better i.e. on a smaller area.

I can't make sense of either:
"you can't print all the way to %100 with three of the inks"
"you'd have to get 512 of the tones from the black ink only"

> 
> Regards,
> 
> Austin

Roy

Hi Roy,

> I guess you weren't one the 16-bit only users.  Well 15 bits is
> way overkill
> anyway

Well, that depends on what PS removes!  If the file is high bit justified,
and it removes the low bit, that's OK.  If it's high bit justified and it
removes the high bit, that's bad.  And converse for low bit justification.

> Computers in general use signed arithmetic so a 16 bit number actually
> goes from -2^15 to +2^15-1  or -32768 to 32767.   I suspect that they
> just use the positive numbers.

16 bits IS 16 bits.  What it represents is entirely different though.  There
is hardware (specifically in the ALU) that can set flags and do arithmetic
based on signed numbers as well as unsigned numbers...and obviously software
does what it does, but because a number is 16 bits, that does not mean it
has to be treated as a signed number.

> It would also have a very significant
> performance benefit --- like 20% faster or even more.   Why?  With
> every single operation on a pixel value you need to check for overflow
> or underflow of the value.  Using just 15 bits means that the top bit
> should always be 0, overflow or underflow would be characterized by
> the top bit being a 1.

CPUs have overflow flags (as does the x86 architecture)...and a bit (not
part of the 16 bits) gets set when the result of an arithmetic operation
creates an overflow condition.  This bit can be tested in a single assembly
instruction and cause a branch.

> This is very easy and FAST to check.  In order
> to do 16 bit unsigned arithmetic, one would actually have to perform
> every operation in 32 bit mode so the over/under flow info wouldn't
> be lost.

Using the overflow is equally as fast, if not even faster...as I don't have
my x86 instruction cycle book handy, just from the CPUs I've designed, it
should take less cycles to check and branch on a flag, then it should to
check the high bit and branch from it.

I believe the x86 has a JO and JNO instruction, jump on overflow, and jump
if no overflow...I believe there is also a JS, jump on sign...but I don't
remember the cycle times on each.  I haven't done any x86 assembly in
probably 10 years.  Anyway, I don't know that I believe it actually saves
any time...

> There's nothing wrong with dithering upon dithering.

I guess that depends on what you mean by wrong...but you may very well be
right, I just don't know what it'll do.

> > > Its just that PS limits how accurate you can specify the
> adjustment curve.
> >
> > Understood.  I still don't know how the printer driver etc. handles the
> > Rourke output methodology though...
>
> There's nothing particularly special about it.

Well, then, what, exactly, does it do?

> > > > still sent to the printer driver, which only handles 8 bits
> > > anyway...but I
> > > > guess if it is in fact printing 8 bits/channel (and in this case, it
> > > > actually is), you could theoretically get the additional tones
> > > (though it
> > > > isn't 256 x 4 BTW, since you can't print all the way to %100
> > > with three of
> > > > the inks...and some tones would be duplicated etc....which,
> > > this argument,
> > > > in and of it self, also brings me to question Cone's
> claim...since you'd
> > > > have to get 512 of the tones from the black ink only etc.).
> >
> > What did you think of the above paragraph?
>
> I not really sure I understand what's really being said or asked, but I'll
> try.   It you start out with an 8 bit grayscale you have 256 possible
> values.  When you convert to RGB you still have only 256 values,

How's that?

> likewise you adjust curves, you still have only 256 values.
> Sure there's lots more bits but only 256 combinations will be used.
> The 4 shades of ink doesn't increase the number of grays either.
> It just makes it do a better job of getting 256 levels.

The number of inks has nothing to do with the number of levels.  It makes
the area required to get N levels smaller.

> So I don't
> buy any 256*4 calculation for ONE pixel.  Its the averaging of
> MULTIPLE pixels that gives you more gray values -- that's the
> only way you can get more grays.

You can get infinite grays from one color given an infinite area with which
to dither...for one pixel.

> Note that the averaging can
> happen in many ways, explicitly in the driver, ink bleed on the
> paper, limited resolution of our eyes, or measuring area of the
> densitometer.


> The 4 inks are a big help in making the averaging
> work better i.e. on a smaller area.
>
> I can't make sense of either:
> "you can't print all the way to %100 with three of the inks"

It's simple.  If one ink is %100 black,  next is %75, next is %50, next is
%25, then you simply can't get the full range of tones from any of the inks
but the %100 ink.

I believe the tones you get from the other inks are merely duplicate
tones...but because you can now intermix the four inks, your dither can
occupy a smaller area.  I don't believe it gives you more tones, simply
smaller area...now you could increase the area used now, and that would
increase the number of tones.  I'd have to think about this a bit.
Certainly multiple graytone ink printing is a new thing to me, which is why
I'm trying to understand it a bit more.  I don't believe it's as "obvious"
how it works as some people think it is.

Austin

As far as the 1000 tones issue goes, I believe I'm not going to get a "good"
answer from Jon.  He said basically (no, I'm not quoting) "It's done by
geniuses...and mere mortals would simply not understand.  We should just be
grateful that we have been given such greatness."

I respect Jon a lot, as well as his products...but I just don't like the
"it's done by magic" answers I seem to get when I ask "tough" questions of
the Piezo product.

It's still a great product, whether I believe it only produces between 100
and 200 tones, or 1000 tones...or it really prints at 2160 or only 1440...

Austin

Hi Austin,

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
> Hi Roy,
> 
> > I guess you weren't one the 16-bit only users.  Well 15 bits is
> > way overkill
> > anyway
> 
> Well, that depends on what PS removes!  If the file is high bit justified,
> and it removes the low bit, that's OK.  If it's high bit justified and it
> removes the high bit, that's bad.  And converse for low bit justification.

Photoshop is in its 7th version, its Adobe's flagship product, thousands of
people use and make there living using it, so let me ask you:
What do you think PS does??  The right thing or the wrong thing??

> 
> > Computers in general use signed arithmetic so a 16 bit number actually
> > goes from -2^15 to +2^15-1  or -32768 to 32767.   I suspect that they
> > just use the positive numbers.
> 
> 16 bits IS 16 bits.  What it represents is entirely different though.  There
> is hardware (specifically in the ALU) that can set flags and do arithmetic
> based on signed numbers as well as unsigned numbers...and obviously software
> does what it does, but because a number is 16 bits, that does not mean it
> has to be treated as a signed number.
> 
> > It would also have a very significant
> > performance benefit --- like 20% faster or even more.   Why?  With
> > every single operation on a pixel value you need to check for overflow
> > or underflow of the value.  Using just 15 bits means that the top bit
> > should always be 0, overflow or underflow would be characterized by
> > the top bit being a 1.
> 
> CPUs have overflow flags (as does the x86 architecture)...and a bit (not
> part of the 16 bits) gets set when the result of an arithmetic operation
> creates an overflow condition.  This bit can be tested in a single assembly
> instruction and cause a branch.
> 
> > This is very easy and FAST to check.  In order
> > to do 16 bit unsigned arithmetic, one would actually have to perform
> > every operation in 32 bit mode so the over/under flow info wouldn't
> > be lost.
> 
> Using the overflow is equally as fast, if not even faster...as I don't have
> my x86 instruction cycle book handy, just from the CPUs I've designed, it
> should take less cycles to check and branch on a flag, then it should to
> check the high bit and branch from it.
> 
> I believe the x86 has a JO and JNO instruction, jump on overflow, and jump
> if no overflow...I believe there is also a JS, jump on sign...but I don't
> remember the cycle times on each.  I haven't done any x86 assembly in
> probably 10 years.  Anyway, I don't know that I believe it actually saves
> any time...

You don't really think PS is written in assembly language, do you? 
It's almost surely written in C.  Neither C nor any other high level language
has direct access to CPU flags.  I've designed and written hundreds of
thousands of line of code, in lots of assembly languages and in C.  So
I know its much harder and slower using all 16 bits.

Example: a and b are pixel values, let's add them and put result in c.

For 15 bits stuff it would be -- with all arithmetic 16 bit:
  c = a + b;
  if (c<0) c = 32767;

For 16 bit, all values must be converted to 32 bits;
  tempa = a;
  tempb = b;
  tempc = tempa + tempb;
  if (tempc > 32767) tempc = 32767
  c = tempc;

It could be written more compactly but all the operations must be there.
Anyway this will take a lot more time -- probably more than double.

> 
> > There's nothing wrong with dithering upon dithering.
> 
> I guess that depends on what you mean by wrong...but you may very well be
> right, I just don't know what it'll do.
> 
> > > > Its just that PS limits how accurate you can specify the
> > adjustment curve.
> > >
> > > Understood.  I still don't know how the printer driver etc. handles the
> > > Rourke output methodology though...
> >
> > There's nothing particularly special about it.
> 
> Well, then, what, exactly, does it do?
> 
> > > > > still sent to the printer driver, which only handles 8 bits
> > > > anyway...but I
> > > > > guess if it is in fact printing 8 bits/channel (and in this case, it
> > > > > actually is), you could theoretically get the additional tones
> > > > (though it
> > > > > isn't 256 x 4 BTW, since you can't print all the way to %100
> > > > with three of
> > > > > the inks...and some tones would be duplicated etc....which,
> > > > this argument,
> > > > > in and of it self, also brings me to question Cone's
> > claim...since you'd
> > > > > have to get 512 of the tones from the black ink only etc.).
> > >
> > > What did you think of the above paragraph?
> >
> > I not really sure I understand what's really being said or asked, but I'll
> > try.   It you start out with an 8 bit grayscale you have 256 possible
> > values.  When you convert to RGB you still have only 256 values,
> 
> How's that?

Well each of the 256 possible gray values converts into a particular
combination of R,G,and B values.  Every time a certain gray value comes
along it'll convert to the same RGB combo.  So there's still only going
to be 256 RGB combinations actually present.  This is also true after
applying curves -- again each of the 256 RGB combos will convert into
a new combo but there can only be 256.

> 
> > likewise you adjust curves, you still have only 256 values.
> > Sure there's lots more bits but only 256 combinations will be used.
> > The 4 shades of ink doesn't increase the number of grays either.
> > It just makes it do a better job of getting 256 levels.
> 
> The number of inks has nothing to do with the number of levels.  It makes
> the area required to get N levels smaller.

Right.
> 
> > So I don't
> > buy any 256*4 calculation for ONE pixel.  Its the averaging of
> > MULTIPLE pixels that gives you more gray values -- that's the
> > only way you can get more grays.
> 
> You can get infinite grays from one color given an infinite area with which
> to dither...for one pixel.

The point is if you only give the driver 256 different values it can only
do 256 different things.

> 
> > Note that the averaging can
> > happen in many ways, explicitly in the driver, ink bleed on the
> > paper, limited resolution of our eyes, or measuring area of the
> > densitometer.
> 
> 
> > The 4 inks are a big help in making the averaging
> > work better i.e. on a smaller area.
> >
> > I can't make sense of either:
> > "you can't print all the way to %100 with three of the inks"
> 
> It's simple.  If one ink is %100 black,  next is %75, next is %50, next is
> %25, then you simply can't get the full range of tones from any of the inks
> but the %100 ink.

Ok, I see what your saying. Actually you don't use any individual ink for the
full range.  The idea is "partitioned" use of the inks.  There is actually
lots of overlap, but conceptually think of it like this:  The darkest 25%  
(100% to 75%) of the tones are all done by the 100% black ink. 
The next 25%  (75% to 50%) is done by the 75% black ink, the next 25%
(50% to 25%) is done by the 50% black ink, and finally the lightest 25%
(25% to 0%) is done by the lightest 25% black ink.  The overlap and
smooth joining of the partitions is tricky -- this is where Paul Roark
has spent many, many hours designing curves to create this partitioning.
The Piezo software does the same thing, but of course its "canned" and
we can't see the details.  Jon Cone likes to call it magic but its really
quite simple in concept.  I think he feels that keeping a little mystery
helps maintain the "value" of his system.

> 
> I believe the tones you get from the other inks are merely duplicate
> tones...but because you can now intermix the four inks, your dither can
> occupy a smaller area.  I don't believe it gives you more tones, simply

Have you ever seen the book, "Real World Scanning and Halftones" by
Blatner, Fleishman, and Roth?  I've found it to be very informative.
It doesn't go into this quadtone stuff but its a real good basis for
how to think about printing gray scale using halftones or dithering.

> smaller area...now you could increase the area used now, and that would
> increase the number of tones.  I'd have to think about this a bit.
> Certainly multiple graytone ink printing is a new thing to me, which is why
> I'm trying to understand it a bit more.  I don't believe it's as "obvious"
> how it works as some people think it is.

Well like many things, when you don't understand it its mysterious and
complicated, but once you figure it out its easy and maybe even obvious.

> 
> Austin

I was thinking of creating some of those step wedge and gradient files
that have been talked about -- and some others that may be useful.
I'm not running piezo lately and don't have access to a densitometer
more sensitive than 0.01D density units.  Would you be interested and
able to print some of these out and measure them?  I think it would
be useful information.

Roy

> > > I guess you weren't one the 16-bit only users.  Well 15 bits is
> > > way overkill
> > > anyway
> >
> > Well, that depends on what PS removes!  If the file is high bit
> justified,
> > and it removes the low bit, that's OK.  If it's high bit
> justified and it
> > removes the high bit, that's bad.  And converse for low bit
> justification.
>
> Photoshop is in its 7th version, its Adobe's flagship product,
> thousands of
> people use and make there living using it, so let me ask you:
> What do you think PS does??  The right thing or the wrong thing??

Hi Roy,

I know HDR files are low bit justified...and what you want to do with them
is set the setpoints, and expand the range over the entire 16 bits before
doing tonal manipulations...so in this case, clipping either bit doesn't
work, unless when you expand it, you only expand it to the 15th bit...  Is
that what it does, lop off the high bit?

> You don't really think PS is written in assembly language, do you?

Perhaps some routines are, but obviously, duh, Roy, the whole thing isn't.
But that was not the point.  EVERYTHING that runs on a CPU is in machine
language...of which the assembler is merely a mnemonic for.

> It's almost surely written in C.  Neither C nor any other high
> level language
> has direct access to CPU flags.

Actually, that is not true.  Any good C compiler will take advantage of
things like that when they can.

> I've designed and written hundreds of
> thousands of line of code, in lots of assembly languages and in C.  So
> I know its much harder and slower using all 16 bits.

I disagree, and I've also written hundreds of thousands of lines of code.
People can write good code, people can write bad code...people can
intentionally write very good code.

> > > > What did you think of the above paragraph?
> > >
> > > I not really sure I understand what's really being said or
> asked, but I'll
> > > try.   It you start out with an 8 bit grayscale you have 256 possible
> > > values.  When you convert to RGB you still have only 256 values,
> >
> > How's that?
>
> Well each of the 256 possible gray values converts into a particular
> combination of R,G,and B values.  Every time a certain gray value comes
> along it'll convert to the same RGB combo.  So there's still only going
> to be 256 RGB combinations actually present.  This is also true after
> applying curves -- again each of the 256 RGB combos will convert into
> a new combo but there can only be 256.

There are four inks.  The inks are CMYK, not RGB.  Why on earth would you
convert grayscale to RGB for a four ink system?  Are you saying that's what
the Rourke curves do?

BTW, in PS, when reading the grayscale file in RGB, all three values R, G
and B are the same as the grayscale value...

> > > The 4 inks are a big help in making the averaging
> > > work better i.e. on a smaller area.
> > >
> > > I can't make sense of either:
> > > "you can't print all the way to %100 with three of the inks"
> >
> > It's simple.  If one ink is %100 black,  next is %75, next is
> %50, next is
> > %25, then you simply can't get the full range of tones from any
> of the inks
> > but the %100 ink.
>
> Ok, I see what your saying. Actually you don't use any individual
> ink for the
> full range.

I never said that you do.  I said that the only ink that is CAPABLE of
producing the full range is the %100 ink.

> The idea is "partitioned" use of the inks.  There is actually
> lots of overlap, but conceptually think of it like this:  The
> darkest 25%
> (100% to 75%) of the tones are all done by the 100% black ink.
> The next 25%  (75% to 50%) is done by the 75% black ink, the next 25%
> (50% to 25%) is done by the 50% black ink, and finally the lightest 25%
> (25% to 0%) is done by the lightest 25% black ink.

I understand that is one way of doing it, I hadn't said otherwise.

> The overlap and
> smooth joining of the partitions is tricky -- this is where Paul Roark
> has spent many, many hours designing curves to create this partitioning.

I would believe that.  I've never done any design work using quadtone inks,
so this (thinking about dithering with quadtone inks) is all new to me.

> The Piezo software does the same thing, but of course its "canned" and
> we can't see the details.  Jon Cone likes to call it magic but its really
> quite simple in concept.  I think he feels that keeping a little mystery
> helps maintain the "value" of his system.

Yes, I agree.

> >
> > I believe the tones you get from the other inks are merely duplicate
> > tones...but because you can now intermix the four inks, your dither can
> > occupy a smaller area.  I don't believe it gives you more tones, simply
>
> Have you ever seen the book, "Real World Scanning and Halftones" by
> Blatner, Fleishman, and Roth?  I've found it to be very informative.
> It doesn't go into this quadtone stuff but its a real good basis for
> how to think about printing gray scale using halftones or dithering.

Yes, I have the book.  The halftone section is very basic, and nothing more
than a primer on the concept.  As I've been designing halftone algorithms
for longer than the book has been out...for me, there are better books on
theory than this book.  If you want very in-depth theory of standard
halftone/dither methods, and perhaps the bible amongst people who design
dithering algorithms, "Digital Halftoning" by Robert Ulichney, and another
purely theory book, "Digital Color Halftoning" by Henry R. Kang.  Both are
quite boring.  For a read, the book you mention is far better ;-)

> > smaller area...now you could increase the area used now, and that would
> > increase the number of tones.  I'd have to think about this a bit.
> > Certainly multiple graytone ink printing is a new thing to me,
> which is why
> > I'm trying to understand it a bit more.  I don't believe it's
> as "obvious"
> > how it works as some people think it is.
>
> Well like many things, when you don't understand it its mysterious and
> complicated, but once you figure it out its easy and maybe even obvious.

Yeah, but I still don't believe it prints "more than 1000" tones ;-)

> >
> > Austin
>
> I was thinking of creating some of those step wedge and gradient files
> that have been talked about -- and some others that may be useful.
> I'm not running piezo lately and don't have access to a densitometer
> more sensitive than 0.01D density units.  Would you be interested and
> able to print some of these out and measure them?  I think it would
> be useful information.

Of course.  You can simply email the files to me, and I'll be more than
happy to print them out for you.

Regards,

Austin

Hi Austin,
 
> Hi Roy,
> 
> I know HDR files are low bit justified...and what you want to do with them
> is set the setpoints, and expand the range over the entire 16 bits before
> doing tonal manipulations...so in this case, clipping either bit doesn't
> work, unless when you expand it, you only expand it to the 15th bit...  Is
> that what it does, lop off the high bit?

You sure worry about the darnedest things.  I haven't any internal knowledge
of PS, I'm a user and just using it I can see that only 2^15 or 32768
levels of gray exist.  Why, how, where this is done, I can only speculate.
But I've written enough code to see the large performance benefit
from just using 15 bits.  Its clear and obvious to me, certainly it might
not be obvious to someone else.  If I was writing the code I'd make
the same recommendation.

> 
> > You don't really think PS is written in assembly language, do you?
> 
> Perhaps some routines are, but obviously, duh, Roy, the whole thing isn't.
> But that was not the point.  EVERYTHING that runs on a CPU is in machine
> language...of which the assembler is merely a mnemonic for.
> 
> > It's almost surely written in C.  Neither C nor any other high
> > level language
> > has direct access to CPU flags.
> 
> Actually, that is not true.  Any good C compiler will take advantage of
> things like that when they can.
> 
> > I've designed and written hundreds of
> > thousands of line of code, in lots of assembly languages and in C.  So
> > I know its much harder and slower using all 16 bits.
> 
> I disagree, and I've also written hundreds of thousands of lines of code.
> People can write good code, people can write bad code...people can
> intentionally write very good code.

I can't imagine what code you've written.  Have you ever used a
high level language?  What C construct are you going to use to
test the carry bit out of the last arithmetic add?  Write me the code.
If you prefer a different high level lang, use that.

> 
> 
> There are four inks.  The inks are CMYK, not RGB.  Why on earth would you
> convert grayscale to RGB for a four ink system?  Are you saying that's what
> the Rourke curves do?

Well the Epson drivers take RGB input.  You have to give it what it wants.

> 
> BTW, in PS, when reading the grayscale file in RGB, all three values R, G
> and B are the same as the grayscale value...

Yes, that's why there's only 256 possibilities.

> 
> > The idea is "partitioned" use of the inks.  There is actually
> > lots of overlap, but conceptually think of it like this:  The
> > darkest 25%
> > (100% to 75%) of the tones are all done by the 100% black ink.
> > The next 25%  (75% to 50%) is done by the 75% black ink, the next 25%
> > (50% to 25%) is done by the 50% black ink, and finally the lightest 25%
> > (25% to 0%) is done by the lightest 25% black ink.
> 
> I understand that is one way of doing it, I hadn't said otherwise.

Do you understand how it works and why it is so much better?

> 
> > The overlap and
> > smooth joining of the partitions is tricky -- this is where Paul Roark
> > has spent many, many hours designing curves to create this partitioning.
> 
> I would believe that.  I've never done any design work using quadtone inks,
> so this (thinking about dithering with quadtone inks) is all new to me.

If its new to you, how can you make such assured claims as:
      I still don't believe it prints "more than 1000" tones.

The quad inks give an exponentially better system.  Its huge.
First the 4 inks in any combo of overprint give a 2^4 multplier.
Plus it can be done in a much smaller area.  Droplet sizes multiply again.
Easily dozens or maybe a 100 times better.  Then didn't I calculate
576 pixels under the densitometer?  That's another 500 multiplier.

I'm actually beginning to think the 1000 might be so easy to do that
its not even a big deal.

> >
> > Have you ever seen the book, "Real World Scanning and Halftones" by
> > Blatner, Fleishman, and Roth?  I've found it to be very informative.
> > It doesn't go into this quadtone stuff but its a real good basis for
> > how to think about printing gray scale using halftones or dithering.
> 
> Yes, I have the book.  The halftone section is very basic, and nothing more

How about the stochastic screening.

> than a primer on the concept.  As I've been designing halftone algorithms
> for longer than the book has been out...for me, there are better books on
> theory than this book.  If you want very in-depth theory of standard
> halftone/dither methods, and perhaps the bible amongst people who design
> dithering algorithms, "Digital Halftoning" by Robert Ulichney, and another
> purely theory book, "Digital Color Halftoning" by Henry R. Kang.  Both are
> quite boring.  For a read, the book you mention is far better ;-)

One of the better tech books I've ever read.

> >
> > I was thinking of creating some of those step wedge and gradient files
> > that have been talked about -- and some others that may be useful.
> > I'm not running piezo lately and don't have access to a densitometer
> > more sensitive than 0.01D density units.  Would you be interested and
> > able to print some of these out and measure them?  I think it would
> > be useful information.
> 
> Of course.  You can simply email the files to me, and I'll be more than
> happy to print them out for you.

But can you get use of a densitometer better than 0.01D ?

> 
> Regards,
> 
> Austin

Roy

Hi Roy,

> I can't imagine what code you've written.  Have you ever used a
> high level language?

Er, yes.  I've written a Lisp interpreter as well as a couple of C
compilers.  I've designed and coded at least six OSs as well as done a lot
of Unix kernel and driver work, along with many applications programs...from
a heuristic backgammon playing program to entire embedded control systems.
I've architected some rather large and very complex software (and hardware)
systems.  It's part of what I do for a living, and have been doing for over
25 years.

> What C construct are you going to use to
> test the carry bit out of the last arithmetic add?  Write me the code.
> If you prefer a different high level lang, use that.

That's up to the C compiler what it does.  Different C compilers will do
different things with the same constructs.  You should know that.

> Well the Epson drivers take RGB input.  You have to give it what it wants.

Apparently so.

> > > The idea is "partitioned" use of the inks.  There is actually
> > > lots of overlap, but conceptually think of it like this:  The
> > > darkest 25%
> > > (100% to 75%) of the tones are all done by the 100% black ink.
> > > The next 25%  (75% to 50%) is done by the 75% black ink, the next 25%
> > > (50% to 25%) is done by the 50% black ink, and finally the
> lightest 25%
> > > (25% to 0%) is done by the lightest 25% black ink.
> >
> > I understand that is one way of doing it, I hadn't said otherwise.
>
> Do you understand how it works and why it is so much better?

Why what works?  Why use four inks?  Of course, I've stated how it works,
and what the advantage is many times.

> > > The overlap and
> > > smooth joining of the partitions is tricky -- this is where Paul Roark
> > > has spent many, many hours designing curves to create this
> partitioning.
> >
> > I would believe that.  I've never done any design work using
> quadtone inks,
> > so this (thinking about dithering with quadtone inks) is all new to me.
>
> If its new to you, how can you make such assured claims as:
>       I still don't believe it prints "more than 1000" tones.

I can say what I don't believe very easily...it only means I personally
don't believe it...it doesn't mean it isn't "possible".  Cripes Roy.  Also,
because I have a LOT of experience with dithering algorithms, as well as a
LOT of experience with Piezo, as well as a LOT of experience with darkroom
printing...and with printing in general as well as a LOT of experience with
digital imaging...

> The quad inks give an exponentially better system.

I guess that depends on what your exponent is...  No one disputes it's
better.

> Plus it can be done in a much smaller area.

Do you not read what I write?  I've said that in just about every post...

> Droplet sizes multiply again.

Droplet size is applicable to single ink dithering as well as multiple ink
dither.

> Easily dozens or maybe a 100 times better.  Then didn't I calculate
> 576 pixels under the densitometer?  That's another 500 multiplier.

How's that work?

> How about the stochastic screening.

What about it?  I've done quite a few stochastic screening algorithms.

> > > I was thinking of creating some of those step wedge and gradient files
> > > that have been talked about -- and some others that may be useful.
> > > I'm not running piezo lately and don't have access to a densitometer
> > > more sensitive than 0.01D density units.  Would you be interested and
> > > able to print some of these out and measure them?  I think it would
> > > be useful information.
> >
> > Of course.  You can simply email the files to me, and I'll be more than
> > happy to print them out for you.
>
> But can you get use of a densitometer better than 0.01D ?

Of course.

Austin

> 
> > What C construct are you going to use to
> > test the carry bit out of the last arithmetic add?  Write me the 
code.
> > If you prefer a different high level lang, use that.
> 
> That's up to the C compiler what it does.  Different C compilers 
will do
> different things with the same constructs.  You should know 
that.
> 

I know what C compilers do.  I want to know what YOU are going
to give the C compiler to compile i.e. I want YOUR source
code.  If you've written so much C code you ought to be able to 
write
a couple of lines of C code that adds 2 unsigned 16 bit numbers
and forces the result to the maximum unsigned 16 bit number if 
there is
overflow.  I want ordinary C code that could be compiled on
any computer with a C compiler on it and will work identically
and correctly on every single one.

Roy

All,

I'm wondering where you all are getting clear print protectors for exchanges
etc.  I'm looking not only for exchanges but also to protect matted prints
for sale at art fairs and galleries.  Tom O'Connell sent me a link to
http://clearbags.com and they look pretty good but I wonder what else is out
there.  These need to be crystal clear so that the prints don't lose
contrast and color saturation when viewed.  I've looked at
http://www.lightimpressiondirect.com and in their catalog but they don't
seem to have what I'm looking for.  Thanks for your help!

Lawrence

----------------------------------
Lawrence W. Smith Photography
http://www.lwsphoto.com
lsmith@...
----------------------------------

Lawrence, try filmguard. They have an add in Outdiir Photography for 
Digital Output Sleeving. Toll free phone 800 777-7744 or 
http://www.filmguard.com. They have free sample available

Vinny
http://wulfsden.com



--- In DigitalBlackandWhiteThePrint@y..., Lawrence Smith 
<lsmith@l...> wrote:
> All,
> 
> I'm wondering where you all are getting clear print protectors for 
exchanges
> etc.  I'm looking not only for exchanges but also to protect matted 
prints
> for sale at art fairs and galleries.  Tom O'Connell sent me a link 
to
> http://clearbags.com and they look pretty good but I wonder what 
else is out
> there.  These need to be crystal clear so that the prints don't lose
> contrast and color saturation when viewed.  I've looked at
> http://www.lightimpressiondirect.com and in their catalog but they 
don't

> seem to have what I'm looking for.  Thanks for your help!
> 
> Lawrence
> 
> ----------------------------------
> Lawrence W. Smith Photography
> http://www.lwsphoto.com
> lsmith@l...
> ----------------------------------

At 07:45 PM 8/6/2002, Austin wrote:
>There are four inks.  The inks are CMYK, not RGB.  Why on earth would you
>convert grayscale to RGB for a four ink system?  Are you saying that's what
>the Rourke curves do?

Here's a quote from the MIS website (www.inksupply.com) instructions for 
the Roark workflow:

"1. Edit the image in grayscale mode and convert the mode to RGB only for 
printing and after saving the g/s file.

"2. Load and apply the desired Image Adjustment Curve. (Image, Adjust, 
Curves, Load, vmqxx, Load, OK)

"When a curve is applied, the image will turn nice bright colors, but these 
are false colors. The image is no longer WYSIWYG. This is for printing 
only, and should not be saved over the good grayscale working file. Do not 
attempt to edit the image once the curve has been applied."

Stan

================================
Photography by Stan McQueen
http://www.smcqueen.com

> > > What C construct are you going to use to
> > > test the carry bit out of the last arithmetic add?  Write me the
> code.
> > > If you prefer a different high level lang, use that.
> >
> > That's up to the C compiler what it does.  Different C compilers
> will do
> > different things with the same constructs.  You should know
> that.
> >
>
> I know what C compilers do.  I want to know what YOU are going
> to give the C compiler to compile i.e. I want YOUR source
> code.  If you've written so much C code you ought to be able to
> write
> a couple of lines of C code that adds 2 unsigned 16 bit numbers
> and forces the result to the maximum unsigned 16 bit number if
> there is
> overflow.  I want ordinary C code that could be compiled on
> any computer with a C compiler on it and will work identically
> and correctly on every single one.

Roy, you're being silly.  The world doesn't work that way.  Good programmers
understand their tools, and typically know what their C compiler of choice
is going to do in cases that are important...and they look at the output of
the compiler to see what it's doing, or they simply write that routine in
assembly language.

Austin

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" 
<darkroom@i...> wrote:
> 
> > > > What C construct are you going to use to
> > > > test the carry bit out of the last arithmetic add?  Write me 
the
> > code.
> > > > If you prefer a different high level lang, use that.
> > >
> > > That's up to the C compiler what it does.  Different C 
compilers
> > will do
> > > different things with the same constructs.  You should 
know
> > that.
> > >
> >
> > I know what C compilers do.  I want to know what YOU are 
going
> > to give the C compiler to compile i.e. I want YOUR source
> > code.  If you've written so much C code you ought to be able 
to
> > write
> > a couple of lines of C code that adds 2 unsigned 16 bit 
numbers
> > and forces the result to the maximum unsigned 16 bit 
number if
> > there is
> > overflow.  I want ordinary C code that could be compiled on
> > any computer with a C compiler on it and will work identically
> > and correctly on every single one.
> 
> Roy, you're being silly.  The world doesn't work that way.  Good 
programmers
> understand their tools, and typically know what their C compiler 
of choice
> is going to do in cases that are important...and they look at the 
output of
> the compiler to see what it's doing, or they simply write that 
routine in
> assembly language.
> 
> Austin

So, Austin, Jon Cone puts a claim of 1000 gray tones and
you jump all over him to prove him claim.

Now, you make this claim:
"I've written a Lisp interpreter as well as a couple of C 
compilers."

I ask you to give the slightest evidence that this is true.  There
is no way someone could have "written a C compiler" and
not know some of the syntax.  I asked for a very small bit of
code to show that you know something about C.

Your evasiveness is amazing.  Frankly, I'm left with the thought
that you haven't the foggiest idea what the C language is,
and you're just going to try and bluff your way out of it.

Roy

"royvharrington" <roy@...> writes:

> > 
> > > What C construct are you going to use to
> > > test the carry bit out of the last arithmetic add?  Write me the 
> code.
> > > If you prefer a different high level lang, use that.
> > 
> > That's up to the C compiler what it does.  Different C compilers 
> will do
> > different things with the same constructs.  You should know 
> that.
> > 
> 
> I know what C compilers do.  I want to know what YOU are going
> to give the C compiler to compile i.e. I want YOUR source
> code.  If you've written so much C code you ought to be able to 
> write
> a couple of lines of C code that adds 2 unsigned 16 bit numbers
> and forces the result to the maximum unsigned 16 bit number if 
> there is
> overflow.  I want ordinary C code that could be compiled on
> any computer with a C compiler on it and will work identically
> and correctly on every single one.

Heh.  I'd do the arithmetic in 32-bit and then test if the result
exceeded the 16-bit unsigned max and chop it if it did :-).  

Unless hardware or performance constraints mandated some other
approach anyway. 

From which you may deduce that that's not the sort of problem I spend
most of my time on; I fall back on the brute force approach when
possible. 
-- 
David Dyer-Bennet, dd-b@...  /  New TMDA anti-spam in test
 John Dyer-Bennet 1915-2002 Memorial Site http://john.dyer-bennet.net
        Book log: http://www.dd-b.net/dd-b/Ouroboros/booknotes/
         New Dragaera mailing lists, see http://dragaera.info

I am wondering whether this contest between Roy and Austin about 
how is the best programmer needs to be part of a discussion forum 
on printing black and white images. I understand that it began 
with a relevant topic, but it seems to have become quite another 
thing.


- David

= = = Original message = = =

--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" 
<darkroom@i...> wrote:
> 
> > > > What C construct are you going to use to
> > > > test the carry bit out of the last arithmetic add?  Write 
me 
the
> > code.
> > > > If you prefer a different high level lang, use that.
> > >
> > > That's up to the C compiler what it does.  Different C 

compilers
> > will do
> > > different things with the same constructs.  You should 

know
> > that.
> > >
> >
> > I know what C compilers do.  I want to know what YOU are 

going
> > to give the C compiler to compile i.e. I want YOUR source
> > code.  If you've written so much C code you ought to be able 

to
> > write
> > a couple of lines of C code that adds 2 unsigned 16 bit 
numbers
> > and forces the result to the maximum unsigned 16 bit 
number if
> > there is
> > overflow.  I want ordinary C code that could be compiled 
on
> > any computer with a C compiler on it and will work identically
> > and correctly on every single one.
> 
> Roy, you're being silly.  The world doesn't work that way. 
 Good 
programmers
> understand their tools, and typically know what their C compiler 

of choice
> is going to do in cases that are important...and they look 
at the 
output of
> the compiler to see what it's doing, or they simply write that 

routine in
> assembly language.
> 
> Austin

So, Austin, Jon Cone puts a claim of 1000 gray tones and
you jump all over him to prove him claim.

Now, you make this claim:
"I've written a Lisp interpreter as well as a couple of C 
compilers."

I ask you to give the slightest evidence that this is true.  
There
is no way someone could have "written a C compiler" and
not know some of the syntax.  I asked for a very small bit of
code to show that you know something about C.

Your evasiveness is amazing.  Frankly, I'm left with the thought
that you haven't the foggiest idea what the C language is,
and you're just going to try and bluff your way out of it.

Roy
 



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> I am wondering whether this contest between Roy and Austin about
> how is the best programmer needs to be part of a discussion forum
> on printing black and white images. I understand that it began
> with a relevant topic, but it seems to have become quite another
> thing.

It can be hazardous too. I think I'm getting RSI from deleting the multitude
of messages from this thread.

--- In DigitalBlackandWhiteThePrint@y..., 
<david_bookbinder@s...> wrote:
> I am wondering whether this contest between Roy and Austin 
about 
> how is the best programmer needs to be part of a discussion 
forum 
> on printing black and white images. I understand that it began 
> with a relevant topic, but it seems to have become quite 
another 
> thing.
> 
> 
> - David

Yes, David, you're right.  I apologize to the group for contributing
to prolonging this wandering thread.  I'm done.  In fact I'm
going to be away soon for a couple of weeks and can't read or
post anyway.

Roy

> So, Austin, Jon Cone puts a claim of 1000 gray tones and
> you jump all over him to prove him claim.
>
> Now, you make this claim:
> "I've written a Lisp interpreter as well as a couple of C
> compilers."
>
> I ask you to give the slightest evidence that this is true.

Roy, cut the crap.  I'm not being evasive, this whole discussion is OFF
TOPIC and simply just foolish, and I'm not interested in playing your little
game.  I am not peddling a commercial product that makes a claim as such, so
I have no need to prove anything to you.  You can simply take my word for
what I have done, or believe I'm lying about my experience, and I find it in
VERY bad form that you would even make such an implication.  I really don't
care what you believe or not.

If you simply don't believe anyone can write a C compiler, and then a C
program, that allows the use of the overflow flag, that's for you to
believe.  I KNOW it can be done.  It's NOT rocket science.

Austin

what gives with the usual crappy Yahoo service.

I set my preference to nomail and the message still keep coming?

I guess they'll just have to keep dealing with all the bounces soon...

tim