Digital BW, The Print

The piezo driver has the smoothest midtones and highlights in the known
universe (ok slight exaggeration). Now it is available on its own (good
marks for ethics) use it with MIS FS for a really cheap solution. I've seen
samples of the new Piezotones and whilst I like them - they are not worth
their European price over FS for me.

Julian
----- Original Message -----
From: "Larry Ostrom" <ostrom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Monday, July 15, 2002 8:59 PM
Subject: [Digital BW] Re: mis-vm / piezo


> Greetings;  I'm shooting head and shoulders portraits, 2 1/4 B&W
> negs. polaroid ss120 scans, outputting to an epson 1200, eam paper,
> mis-vm ink, + roark curves.  The problem is the light grey tones in
> the face, they aren't all there, not a smooth transition.
> (especially zone V to zone V111 for all us darkroom printers).  My
> question is, would the piezography photoshop driver smooth out these
> tones, or am I doing something wrong with my PS6 procedure.  Or is
> the conventional darkroom still the best place for portraits (heads)
> thanks
> --
>   ******* ********
> Ostrom Photography
>   ostrom@...
>     ******  *******
>
> [Non-text portions of this message have been removed]
>
>
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Both the Piezo and Epson RGB workflows can produce very good prints.  On the
other hand, I have never seen a perfectly smooth grayscale ramp.  If a
critical tone in a print falls in a spot where the particular workflow and
printer happen to have a flat spot, it can obviously have a detrimental
affect on the final print.

To see the types of defects that affect these workflows, see the comparison
I put in the Files section of this forum.  What I did with these 21-step
test strip prints is run a Photoshop gradient the opposite direction of the
test strip's ramp in order to cancel out the smooth ramp.  Then I increased
contrast to accentuate the defects -- those areas that deviated from a
perfect ramp.

See "Ramp-smoothness.jpg" in the "Image processing" folder of the Files
section of this forum.  The Files section is at
http://groups.yahoo.com/group/DigitalBlackandWhiteThePrint/files/

(There are a couple of lines in the 95% and 100% patches that are scanner
defects.)

The Piezo driver does a very good job most of the time, and the Epson driver
with and RGB curve can do a very good job also.

I know from the curves I've seen that the RGB workflows can be affected by
the particular printer characteristics -- that is, some printers work better
with the workflows than others.  I suspect that is also true of the Piezo
driver, but I do not have enough of a sample to know what the range of
performance is.

Of course, not all the RGB curves out there are of equal quality either.

My gut reaction is that the Piezo driver is less affected by
printer-to-printer variation, but then, if your particular printer is one
that doesn't do well with a workflow, the RGB curves approach allows you to
fine-tune your machine.

The RGB curves are also affected by variables such as settings in the Color
Settings of Photoshop and the Epson driver.  It also looks like PS 7 is
different than PS 6, though I still do not have a copy of PS 7 to see what
might be going on.

With the Piezo driver now being separately available, it probably is worth
trying if you're having trouble.

On the other hand, if you like a variable-tone inkset and are having
trouble, learning how to tweak the curves makes a lot of sense.  If you can
identify the area of the problem with the eyedropper in the image file, then
make some blocks that are 1% different in that area and add them to the
21-step test chart, the way the top and bottom 5% have been done with the
posted 21-step test file.  This will allow you to see whether you are
getting a smooth response in the area of concern.  Once you identify the
problem, you can go to the curves and correct it.

The RGB curve is usually mostly free of points.  (The limited number of
points that Photoshop allows per curve is a problem.)  For very small
wiggles at the ends of the curve, I've been using this RGB curve to correct
the situation.  By putting enough points on the 45 degree line (input =
output) you can hold most of the curve as is while adding a bunch of points
in the area where the problem is.  By doing this you can often get enough
points in the critical area of the graph to do the job.

Good luck.

Paul
http://www.PaulRoark.com

So you don't have to go through the pushups and so I can be more 
indivdually customised about it, can I do something like what you 
describe below? Except print out the step wedge and bring it to a lab 
with a densitometer that reads CMYK?

I guess a question might be how to vary the cmy to get cool, neutral, 
or warm curves to taste- do you weight the midtones with more color, 
or is it more linear? I'd expect the k values read by the densitometer 
to be more straightforward...or maybe total ink put down expressed as 
a K reading if it can read it like that.

Maybe one way is if I can print out some known good step wedges that 
work with my paper in PS6, then I can read the values and just try to 
duplicate them say at a different dpi or PS7 or workspace 
conversion...whatever.

Does any of this make sense? Maybe I'm just eternally confused by PS7 
hijinks these days...<g>
Jim H.



--- In DigitalBlackandWhiteThePrint@y..., "Paul Roark" 
<paul.roark@v...> wrote:

  It also looks like PS 7 
is
> different than PS 6, though I still do not have a copy of PS 7 to 
see what
> might be going on.
> 
> With the Piezo driver now being separately available, it probably is 
worth
> trying if you're having trouble.
> 
> On the other hand, if you like a variable-tone inkset and are having
> trouble, learning how to tweak the curves makes a lot of sense.  If 
you can
> identify the area of the problem with the eyedropper in the image 
file, then
> make some blocks that are 1% different in that area and add them to 
the
> 21-step test chart, the way the top and bottom 5% have been done 
with the
> posted 21-step test file.  This will allow you to see whether you 
are
> getting a smooth response in the area of concern.  Once you identify 
the
> problem, you can go to the curves and correct it.
> 
> The RGB curve is usually mostly free of points.  (The limited number 
of
> points that Photoshop allows per curve is a problem.)  For very 
small
> wiggles at the ends of the curve, I've been using this RGB curve to 
correct
> the situation.  By putting enough points on the 45 degree line 
(input =
> output) you can hold most of the curve as is while adding a bunch of 
points
> in the area where the problem is.  By doing this you can often get 
enough

> points in the critical area of the graph to do the job.
> 
> Good luck.
> 
> Paul
> http://www.PaulRoark.com

Jim,

You wrote:

>... can I do something like what you
>describe below? Except print out the step wedge and bring
>it to a lab with a densitometer that reads CMYK?

I suppose.  I used to use a flatbed scanner to read the test strips.
However, they are not, in my experience, as good as a densitometer.  In
fact, about half of the ones out there with the people who wanted to help in
making curves were totally unusable.

For just getting even steps, however, a scanner, or even just using your
eyes can do a very decent job.

>I guess a question might be how to vary the cmy to get cool, neutral,
>or warm curves to taste- do you weight the midtones with more color,
>or is it more linear?

The paper sets the white point, and the black ink the black point.  I do
role off the gamuts to these points as I approach them.  So, the midtones
between 25% and 75% will be about the same tone/gamut, but outside those
points the curve approaches the black ink and paper white.

> I'd expect the k values read by the densitometer
>to be more straightforward...

The X-Rite makes the job easier and more accurate (I hope -- I just trust
the X-Rite to be giving me true values).

>Maybe one way is if I can print out some known good step wedges that
>work with my paper in PS6, then I can read the values and just try to
>duplicate them say ...

I originally just visually matched my Piezo output.  With tone is a little
more difficult, but with the density of the steps, it's really not a bad way
to go.

Paul
http://www.PaulRoark.com
_________________________________________________


--- In DigitalBlackandWhiteThePrint@y..., "Paul Roark"
<paul.roark@v...> wrote:

  It also looks like PS 7
is
> different than PS 6, though I still do not have a copy of PS 7 to
see what
> might be going on.
>
> With the Piezo driver now being separately available, it probably is
worth
> trying if you're having trouble.
>
> On the other hand, if you like a variable-tone inkset and are having
> trouble, learning how to tweak the curves makes a lot of sense.  If
you can
> identify the area of the problem with the eyedropper in the image
file, then
> make some blocks that are 1% different in that area and add them to
the
> 21-step test chart, the way the top and bottom 5% have been done
with the
> posted 21-step test file.  This will allow you to see whether you
are
> getting a smooth response in the area of concern.  Once you identify
the
> problem, you can go to the curves and correct it.
>
> The RGB curve is usually mostly free of points.  (The limited number
of
> points that Photoshop allows per curve is a problem.)  For very
small
> wiggles at the ends of the curve, I've been using this RGB curve to
correct
> the situation.  By putting enough points on the 45 degree line
(input =
> output) you can hold most of the curve as is while adding a bunch of
points
> in the area where the problem is.  By doing this you can often get
enough

> points in the critical area of the graph to do the job.
>
> Good luck.
>
> Paul
> http://www.PaulRoark.com