Digital BW, The Print

Nick,
 
first of all congratulations for your amazing work (from what I can see on
the web). Second, now you made me curious about what Joe may have taught you
to reduce apparent graininess in your photos :-)
Seriously, how can you get the same results without using levels or curves,
or using them less than you would?
 
Alessandro

-----Original Message-----
From: nick90290 [mailto:NickBrandt@...]
Sent: Thursday, June 05, 2003 19:22
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: Re: [Digital BW] Exhibition of my photos using IJC in NY


 <snip> 

 ... after working on the photos with Joe at Bowhaus on the NY exhibition in
the 
last month, he taught me so much about avoiding graininess (I had
been using Levels way more than I should have, incurring unecessary 
grain) that all the photos from the NY exhibition have been pretty 
much re-worked from scratch and look much better/less grainy.

N



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

Hi Alessandro

Thanks for the compliments on the photos. Especially considering you 
saw a bunch of pokey little 3" inch images on the web. I'm very 
flattered.

In response to your answer, firstly let me say I feel very foolish
and dumb having been using Levels at all to create the majority of my 
contrast, since it was making many of my images way more grainy than 
they ever needed to be. 

The thing I found with levels is if you have a fairly grainy image to 
begin with, you increase the contrast of each invidual 'blob' of
grain to the next. Obviously working in Curves is better and helps to 
quite a degree. 

But what I now do - which is very painstaking, is try and create 
nearly all my contrast in the image, down to the smallest detail, 
through elaborate dodging and burning with the brush set to
mid-tones. 
That way, all the 'blobs' of grain are pretty similar to the original 
flat scan one started with. 

I was shocked at the difference it made when I started again from 
scratch on a number of photos. Grainy photos done the old way at 
11"x14", when re-done using my new time-consuming method, looked 
almost devoid of grain blown up to 20"x24". So when I did add more 
overall contrast to the new image in Curves , it was only a pretty 
small amount, that did little to make the image more grainy. 

I should add that I only have this problem with grainy images - the 
images shot on T-Max 100 (6x7 format) generally are grainless enough 
that they can handle some crude levels layers. 

Nick

................................

Will something like the X-Rite 308 work?

Also, the DTP autoscans?  Seems like you just have to generate a color chart
each time.

Sorry to be so unknowing about these.

Sethb

Hi Nick-

A very interesting (if painstaking) technique! How are you scanning these
images?


Bill Morse
PhotoProspect
Cambridge, MA USA


on 6/6/03 11:24 AM, nick90290 wrote:

> Hi Alessandro
> 
> Thanks for the compliments on the photos. Especially considering you
> saw a bunch of pokey little 3" inch images on the web. I'm very
> flattered.
> 
> In response to your answer, firstly let me say I feel very foolish
> and dumb having been using Levels at all to create the majority of my
> contrast, since it was making many of my images way more grainy than
> they ever needed to be.
> 
> The thing I found with levels is if you have a fairly grainy image to
> begin with, you increase the contrast of each invidual 'blob' of
> grain to the next. Obviously working in Curves is better and helps to
> quite a degree. 
> 
> But what I now do - which is very painstaking, is try and create
> nearly all my contrast in the image, down to the smallest detail,
> through elaborate dodging and burning with the brush set to
> mid-tones. 
> That way, all the 'blobs' of grain are pretty similar to the original
> flat scan one started with.
> 
> I was shocked at the difference it made when I started again from
> scratch on a number of photos. Grainy photos done the old way at
> 11"x14", when re-done using my new time-consuming method, looked
> almost devoid of grain blown up to 20"x24". So when I did add more
> overall contrast to the new image in Curves , it was only a pretty
> small amount, that did little to make the image more grainy.
> 
> I should add that I only have this problem with grainy images - the
> images shot on T-Max 100 (6x7 format) generally are grainless enough
> that they can handle some crude levels layers.
> 
> Nick
> 
> ................................
> 
> 
> 
> 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 flames
> - 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/
> 
>

Seth,

don't know about the 308, but any of the DTP autoscans usually assume 
some software support that generates the targets. A simpler instrument would 
be more useful for bw where you really only need to read a few patches (26 in 
the case of IJC) as opposed to color where you can be reading hundreds.

The dilemma for many people who do both color and bw is whether to buy a 
densitometer for a few hunder $ from eBay and then have to buy a fancy strip 
reading spectrophotometer for heavy duty color profiling. It takes jumping 
through a few hoops to get the strip readers to read a simple 26-step 
grayscale a step at a time.

Antonis


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Seth Rossman" 
<seth@m...> wrote:
> Will something like the X-Rite 308 work?
> 
> Also, the DTP autoscans?  Seems like you just have to generate a color 
chart

> each time.
> 
> Sorry to be so unknowing about these.
> 
> Sethb

Thanks, Antonis-

I am only looking to solve two issues.

First is to know when I have reached the D I want for a particular image.

Second, to know if there is a colorcast in the ink so I can correct (?!?!)
it.

Where it has been driving me nuts is doing B&W's from color images.  PS SAYS
the grays are neutral, but I see color in one end or the other.  It would be
simple to just dump the color layers from the images. But, I am laying the
B&W over the color original (in PS), then wanting to print with just certain
"spots" in color.  Therefore, I have to stay in RGB mode.

Does that sound as though I need to have both pieces of equipment?

Seth

=don't know about the 308, but any of the DTP autoscans usually assume 
=some software support that generates the targets. A simpler 
=instrument would 
=be more useful for bw where you really only need to read a few 
=patches (26 in 
=the case of IJC) as opposed to color where you can be reading hundreds.
=
=The dilemma for many people who do both color and bw is 
=whether to buy a 
=densitometer for a few hunder $ from eBay and then have to buy 
=a fancy strip 
=reading spectrophotometer for heavy duty color profiling. It 
=takes jumping 
=through a few hoops to get the strip readers to read a simple 26-step 
=grayscale a step at a time.
=

Nick. I'd be interesting in getting more details about how you go 
about increasing contrast using the dodge/burn tool. Have you seen 
any noise/artifact problems coming up from having to work in 8-bit 
mode to do your burning? Also, doing a quick, unscientific 
comparison, I notice that darkening a bit of sky (viewed at 100% in 
PS) by curves or levels does seem to increase graininess as compared 
to darkening it by using the burn tool OR by decreasing brightness. 
(I'd be interested in hearing what other people have experienced in 
this regard.) Using the burn tool and decreasing brightness seem to 
have about the same effect on grain. And if that is indeed the case, 
then it would seem to be easier and more accurate, at least for large 
tracts of cloudless sky, etc. to create a layer mask on a 8-bit copy, 
save the selection, then import it into the original 16-bit image and 
then darken the selection using decrease in brightness.

Chris Hargens 

  --- In DigitalBlackandWhiteThePrint@yahoogroups.com, Bill Morse 
<willym@b...> wrote:
> Hi Nick-
> 
> A very interesting (if painstaking) technique! How are you scanning 
these
> images?
> 
> 
> Bill Morse
> PhotoProspect
> Cambridge, MA USA
> 
> 
> on 6/6/03 11:24 AM, nick90290 wrote:
> 
> > Hi Alessandro
> > 
> > Thanks for the compliments on the photos. Especially considering 
you
> > saw a bunch of pokey little 3" inch images on the web. I'm very
> > flattered.
> > 
> > In response to your answer, firstly let me say I feel very foolish
> > and dumb having been using Levels at all to create the majority 
of my
> > contrast, since it was making many of my images way more grainy 
than
> > they ever needed to be.
> > 
> > The thing I found with levels is if you have a fairly grainy 
image to
> > begin with, you increase the contrast of each invidual 'blob' of
> > grain to the next. Obviously working in Curves is better and 
helps to
> > quite a degree. 
> > 
> > But what I now do - which is very painstaking, is try and create
> > nearly all my contrast in the image, down to the smallest detail,
> > through elaborate dodging and burning with the brush set to
> > mid-tones. 
> > That way, all the 'blobs' of grain are pretty similar to the 
original
> > flat scan one started with.
> > 
> > I was shocked at the difference it made when I started again from
> > scratch on a number of photos. Grainy photos done the old way at
> > 11"x14", when re-done using my new time-consuming method, looked
> > almost devoid of grain blown up to 20"x24". So when I did add more
> > overall contrast to the new image in Curves , it was only a pretty
> > small amount, that did little to make the image more grainy.
> > 
> > I should add that I only have this problem with grainy images - 
the
> > images shot on T-Max 100 (6x7 format) generally are grainless 
enough
> > that they can handle some crude levels layers.
> > 
> > Nick
> > 
> > ................................
> > 
> > 
> > 
> > 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 
flames
> > - 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/
> > 
> >

Chris writes:

> ... create a layer mask on a 8-bit copy,
> save the selection, then import it into
> the original 16-bit image and then darken
> the selection using decrease in brightness.

Use curves, snapshots, and the history brush instead, that way you never
have to leave 16-bit mode.

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Anthony 
Atkielski" <anthony@a...> wrote:
> Chris writes:
> 
> > ... create a layer mask on a 8-bit copy,
> > save the selection, then import it into
> > the original 16-bit image and then darken
> > the selection using decrease in brightness.
> 
> Use curves, snapshots, and the history brush instead, that way you 
never
> have to leave 16-bit mode.

Hi Anthony

This is a great simple method to enable you to stay in 16-bit. But the 
interesting thing is when I was doing re-grading of my photos for my 
exhibition with Joe Berndt at Bowhaus (the guy behind OPM/IJC) he 
would work on the photo in 8-bit, and only convert it back into 16-bit 
for the actual printing. In other words, he didn't/doesn't seem to 
feel that it makes much difference which you work in - 8 or 16 bit - 
the prints seem  to come out just as good in the final result. 

Antonis, if you're reading this, I'd be curious to know what you feel 
about this....

Nick


........

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Bill Morse 
<willym@b...> wrote:
> Hi Nick-
> 
> A very interesting (if painstaking) technique! How are you scanning 
these
> images?
> 
> 
> Bill Morse
> PhotoProspect
> Cambridge, MA USA
> 


Hi Bill

They're pretty much all scanned on a Crossfield Drum Scan at Bowhaus 
at 200 mb size. Occasionally, I'm embarrassed (again!) to admit that 
I've used my Epson 2450 as well, for inexplicably, bizarrely good, 
sharp results. However, I'm plan to get a Nikon 8000 when I get back 
from my next photogrpahic trip.

Nick

..................

>... at Bowhaus (the guy behind OPM/IJC) he
>would work on the photo in 8-bit, and only convert it back
>into 16-bit for the actual printing. ...

This must be the reflection of a strange driver/RIP.  It makes no sense to
me otherwise.

Once you convert to 8 bit you've lost the additional information/grayscale
steps 16 bit can hold.  Conversion back to 16 bits from 8 bits does not
restore those lost steps; it does not add information.  You have the same
number of grayscale steps you had in the 8 bit image, but with a file that
is twice as big.  Why would one do this?

I agree that 8 bits is all that is needed for a fine B&W print, but it is in
the manipulation stage where there is a major loss of information.  When you
apply curves, etc., you lose grayscale steps.  The purpose for keeping the
file in 16 bit as long as possible is usually to have enough extra
steps/information so that when you're done you have at least close to the
256 gray levels that 8 bits can hold.

If you drop much below 256 levels, the quality of the image may suffer.
Take a look at a print of the 100-step test file.  You can clearly see those
steps.  That means that 100 levels is not sufficient for a very fine grain,
clear sky.  (Grain will help to mask this problem if it surfaces -- but that
is not a very attractive remedy.)

Paul
http://www.PaulRoark.com

Paul,

everything you say regarding the effect of the high bits on the actual image 
are undisputable, and certainly something that all bw printmakers should be 
aware of  (much more so than color where you can hide behind 3x or 4x the 
digital information). 

The thing with OPM is that it was built  on (or came from) a 16bit engine,  with 
8bit support only added very recently. Any decent driver needs to work in 16 
bits internally anyway to avoid quantization errors. However, there may be 
weaknesses in the 8-to16 bit internal conversion with OPM, that make it a 
"safer bet" to give it a 16 bit file.  The latter bypasses an extra step in the driver 
and takes out some variables (that only Joe would know to tell you about).

I personally haven't seen a good reason to bumb up the file to 16 bits or to 
even hit 720 dpi unless the initial res is too close to 360 or the file has a lot of 
sharp diagonals etc. But if I ran into any questionable output, those would be 
the first things I would try.

In short, I just wanted to point out that the issue of 8 vs 16bits in this scase is 
solely for the purpose of helping out the driver and has nothing to do with our 
usual concerns of preserving the gray steps in a monochrome image file.

Antonis







--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" 
<paul.roark@v...> wrote:
> 
> >... at Bowhaus (the guy behind OPM/IJC) he
> >would work on the photo in 8-bit, and only convert it back
> >into 16-bit for the actual printing. ...
> 
> This must be the reflection of a strange driver/RIP.  It makes no sense to
> me otherwise.
> 
> Once you convert to 8 bit you've lost the additional information/grayscale
> steps 16 bit can hold.  Conversion back to 16 bits from 8 bits does not
> restore those lost steps; it does not add information.  You have the same
> number of grayscale steps you had in the 8 bit image, but with a file that
> is twice as big.  Why would one do this?
> 
> I agree that 8 bits is all that is needed for a fine B&W print, but it is in
> the manipulation stage where there is a major loss of information.  When 
you

> apply curves, etc., you lose grayscale steps.  The purpose for keeping the
> file in 16 bit as long as possible is usually to have enough extra
> steps/information so that when you're done you have at least close to the
> 256 gray levels that 8 bits can hold.
> 
> If you drop much below 256 levels, the quality of the image may suffer.
> Take a look at a print of the 100-step test file.  You can clearly see those
> steps.  That means that 100 levels is not sufficient for a very fine grain,
> clear sky.  (Grain will help to mask this problem if it surfaces -- but that
> is not a very attractive remedy.)
> 
> Paul
> http://www.PaulRoark.com

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul Roark" 
<paul.roark@v...> wrote:
> 
> >... at Bowhaus (the guy behind OPM/IJC) he
> >would work on the photo in 8-bit, and only convert it back
> >into 16-bit for the actual printing. ...
> 
> This must be the reflection of a strange driver/RIP.  It makes no 
sense to
> me otherwise.
> 
> Once you convert to 8 bit you've lost the additional 
information/grayscale
> steps 16 bit can hold.  Conversion back to 16 bits from 8 bits does 
not
> restore those lost steps; it does not add information.  You have the 
same
> number of grayscale steps you had in the 8 bit image, but with a 
file that
> is twice as big.  Why would one do this?
> 
> I agree that 8 bits is all that is needed for a fine B&W print, but 
it is in
> the manipulation stage where there is a major loss of information.  
When you
> apply curves, etc., you lose grayscale steps.  The purpose for 
keeping the
> file in 16 bit as long as possible is usually to have enough extra
> steps/information so that when you're done you have at least close 
to the
> 256 gray levels that 8 bits can hold.
> 
> If you drop much below 256 levels, the quality of the image may 
suffer.
> Take a look at a print of the 100-step test file.  You can clearly 
see those
> steps.  That means that 100 levels is not sufficient for a very fine 
grain,
> clear sky.  (Grain will help to mask this problem if it surfaces -- 
but that
> is not a very attractive remedy.)
> 
> Paul
> http://www.PaulRoark.com

Hi Paul,

What you say makes total sense, of course. Especially since I consider 
you one of the Godfathers of Digital Black and White Printing! I'm 
curious myself. I'm going to forward your opinion here onto Joe at 
Bowhaus and see why he works this way in OPM/IJC. All I know is I 
can't see the difference between his prints he does from 16-bit and 
8-bit files (acknowledging this is irrelevant on photos that have 
already lost the information due to having been converted to 8-bit 
early on.)

Nick

.

> First is to know when I have reached the D I want for a particular image.

Seth,

this first requirement is easy to achieve with either instrument (densito- or 
spectrophoto-). There is just one caveat: If you are reading actual prints, you 
need something that can reach into the image area, and usually handheld 
instruments are used for that (of either variety).


> 
> Second, to know if there is a colorcast in the ink so I can correct (?!?!)
> it.
> 
> Where it has been driving me nuts is doing B&W's from color images.  PS 
SAYS
> the grays are neutral, but I see color in one end or the other.  It would be
> simple to just dump the color layers from the images. But, I am laying the
> B&W over the color original (in PS), then wanting to print with just certain
> "spots" in color.  Therefore, I have to stay in RGB mode.

Should I assume you are printing on a color printer (i.e. one with a full gamut 
color inkset)? If so, your best bet by far is a color profile that is tweaked to 
maintain the gray axis - not the easiest of excercises. Or else... drivers like 
ImagePrint that have already done the homework for you.  

A spectrophotmeter  is always more appropriate when color is involved. The 
big limitation of  color densitometers is that their built-in cutoff filters are tuned 
to a particular photographic process (E6, C41 etc) and can't read color 
accurately outside of that. 

Antonis

> 
> Does that sound as though I need to have both pieces of equipment?
> 
> Seth
> 
> =don't know about the 308, but any of the DTP autoscans usually assume 
> =some software support that generates the targets. A simpler 
> =instrument would 
> =be more useful for bw where you really only need to read a few 
> =patches (26 in 
> =the case of IJC) as opposed to color where you can be reading hundreds.
> =
> =The dilemma for many people who do both color and bw is 
> =whether to buy a 
> =densitometer for a few hunder $ from eBay and then have to buy 
> =a fancy strip 
> =reading spectrophotometer for heavy duty color profiling. It 
> =takes jumping 
> =through a few hoops to get the strip readers to read a simple 26-step 
> =grayscale a step at a time.
> =

Nick writes:

> ... he would work on the photo in 8-bit, and only
> convert it back into 16-bit for the actual printing.

Converting an 8-bit image to 16-bit just before printing accomplishes
absolutely nothing, except to take up more memory and time.  Once you've
converted to 8-bit, all the 16-bit data is lost, and you won't get it back
again by converting back to 16-bit.  It's a one way street.

> In other words, he didn't/doesn't seem to feel that
> it makes much difference which you work in - 8 or 16 bit -
> the prints seem  to come out just as good in the
> final result.

He has it backwards.  You should do as much as possible in 16-bit, and then
convert to 8-bit only just before printing (if at all), and not the other
way around.

The advantage?  Sixteen-bit files give you a lot more headroom for
manipulation.  For every gray level in an 8-bit file, there are 256
intermediate gray levels in a 16-bit file; so if you want to expand three
gray levels to cover the entire black-to-white range in an image, you can do
it with a 16-bit file and get smooth results, but if you do it with an 8-bit
file, you'll get huge posterization, with only three shades of gray
throughout the image.

I try to stay in 16-bit for as long as possible, but I archive and print in
8-bit (except for the most valuable images, which I archive in 16-bit TIFF,
but I still convert to 8-bit for printing).

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Antonis 
Ricos" <antonisphoto@y...> wrote:
> Paul,
> 
> everything you say regarding the effect of the high bits on the 
actual image 
> are undisputable, and certainly something that all bw 
printmakers should be 
> aware of  (much more so than color where you can hide 
behind 3x or 4x the 
> digital information). 
> 
> The thing with OPM is that it was built  on (or came from) a 
16bit engine,  with 
> 8bit support only added very recently. Any decent driver needs 
to work in 16 
> bits internally anyway to avoid quantization errors. However, 
there may be 
> weaknesses in the 8-to16 bit internal conversion with OPM, 
that make it a 
> "safer bet" to give it a 16 bit file.  The latter bypasses an extra 
step in the driver 
> and takes out some variables (that only Joe would know to tell 
you about).

8 bit  to 16 bit conversion is so straightforward it's hard to
imagine why it would be better to do it before sending data to
OPM.   The only possibility I can think of is doing some of
the processing in 8 bit before converting to 16.  The conversion
should be the very first thing that happens in the driver.
(At least that's what I do in my code).

Roy

> 
> I personally haven't seen a good reason to bumb up the file to 
16 bits or to 
> even hit 720 dpi unless the initial res is too close to 360 or the 
file has a lot of 
> sharp diagonals etc. But if I ran into any questionable output, 
those would be 
> the first things I would try.
> 
> In short, I just wanted to point out that the issue of 8 vs 16bits 
in this scase is 
> solely for the purpose of helping out the driver and has nothing 
to do with our 
> usual concerns of preserving the gray steps in a monochrome 
image file.
> 
> Antonis
> 
> 
> 
> 
> 
> 
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul 
Roark" 
> <paul.roark@v...> wrote:
> > 
> > >... at Bowhaus (the guy behind OPM/IJC) he
> > >would work on the photo in 8-bit, and only convert it back
> > >into 16-bit for the actual printing. ...
> > 
> > This must be the reflection of a strange driver/RIP.  It makes 
no sense to
> > me otherwise.
> > 
> > Once you convert to 8 bit you've lost the additional 
information/grayscale
> > steps 16 bit can hold.  Conversion back to 16 bits from 8 bits 
does not
> > restore those lost steps; it does not add information.  You 
have the same
> > number of grayscale steps you had in the 8 bit image, but 
with a file that
> > is twice as big.  Why would one do this?
> > 
> > I agree that 8 bits is all that is needed for a fine B&W print, 
but it is in
> > the manipulation stage where there is a major loss of 
information.  When 
> you
> > apply curves, etc., you lose grayscale steps.  The purpose for 
keeping the
> > file in 16 bit as long as possible is usually to have enough 
extra
> > steps/information so that when you're done you have at least 
close to the
> > 256 gray levels that 8 bits can hold.
> > 
> > If you drop much below 256 levels, the quality of the image 
may suffer.
> > Take a look at a print of the 100-step test file.  You can clearly 
see those
> > steps.  That means that 100 levels is not sufficient for a very 
fine grain,
> > clear sky.  (Grain will help to mask this problem if it surfaces 
-- but that

> > is not a very attractive remedy.)
> > 
> > Paul
> > http://www.PaulRoark.com

> 8 bit  to 16 bit conversion is so straightforward it's hard to
> imagine why it would be better to do it before sending data to
> OPM.   

I am purely speculating here ... but one can imagine an 8bit->16bit
conversion that is not quite as straightforward and might create
a better image.  The idea would be to make the hi-byte of the 16bit
value equal to the 8bit value, and then put a random value into
the low-byte.   This has the effect of reducing "mock bands" at the
transitions between the 256 values; it is frequently used in 
computer image generation systems.  However, I'd be very surprised
if Photoshop does this when you convert "mode" from 8bit to 16bit,
in which case this wouldn't explain the supposed improvement from
OPM when you give it 16bit images,

John

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, 
"johngeyles" <jge@c...> wrote:
> 
> > 8 bit  to 16 bit conversion is so straightforward it's hard to
> > imagine why it would be better to do it before sending data to
> > OPM.   
> 
> I am purely speculating here ... but one can imagine an 
8bit->16bit
> conversion that is not quite as straightforward and might create
> a better image.  The idea would be to make the hi-byte of the 
16bit
> value equal to the 8bit value, and then put a random value into
> the low-byte.   This has the effect of reducing "mock bands" at 
the
> transitions between the 256 values; it is frequently used in 
> computer image generation systems.  However, I'd be very 
surprised
> if Photoshop does this when you convert "mode" from 8bit to 
16bit,
> in which case this wouldn't explain the supposed improvement 
from
> OPM when you give it 16bit images,
> 
> John

Yes, adding noise to the bottom byte could be done.  But
Photoshop doesn't . It actually takes the 8bit number and
multiplies by 257 -- puts same value in each half of the
16bit value, that way 0 ==> 0 and 255 ==> 65535.

Roy

Ok.  If i scan an image at 8 bits and before I print in on OPM I convert it to 16 
bits in PS7 and save the file,  will the resulting 16 bit image look better than if I had 
saved it at 8 bits and then printed it?

I'm confused.

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Roy Harrington" <roy@h...> 
wrote:

> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, 
> "johngeyles" <jge@c...> wrote:
> > 
> > > 8 bit  to 16 bit conversion is so straightforward it's hard to
> > > imagine why it would be better to do it before sending data to
> > > OPM.   
> > 
> > I am purely speculating here ... but one can imagine an 
> 8bit->16bit
> > conversion that is not quite as straightforward and might create
> > a better image.  The idea would be to make the hi-byte of the 
> 16bit
> > value equal to the 8bit value, and then put a random value into
> > the low-byte.   This has the effect of reducing "mock bands" at 
> the
> > transitions between the 256 values; it is frequently used in 
> > computer image generation systems.  However, I'd be very 
> surprised
> > if Photoshop does this when you convert "mode" from 8bit to 
> 16bit,
> > in which case this wouldn't explain the supposed improvement 
> from
> > OPM when you give it 16bit images,
> > 
> > John
> 
> Yes, adding noise to the bottom byte could be done.  But
> Photoshop doesn't . It actually takes the 8bit number and
> multiplies by 257 -- puts same value in each half of the
> 16bit value, that way 0 ==> 0 and 255 ==> 65535.
> 
> Roy

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "luisvcool" <lvictoria@t...> 
wrote:
> Ok.  If i scan an image at 8 bits and before I print in on OPM I convert it to 16 
> bits in PS7 and save the file,  will the resulting 16 bit image look better than if I had 
> saved it at 8 bits and then printed it?
> 
> I'm confused.
> 


A couple of months ago I discovered that OPM prints from 8-Bit files at resolutions 
under about 450 dpi displayed stair stepped diagonals - at least when examined with 
a loupe. So, I did a series of prints to examine the 8-Bit vs 16-Bit treatment with 
OPM. There was no question that feeding OPM with a 16-Bit file was better than with 
an 8-Bit file. The effect was about the same as resampling an 8-Bit file up by a factor 
of two. An 8-Bit file at 720 dpi produced about the same results as a 16-Bit file at 
360 dpi.

I don't know why this occurs, but I satisfied myself with the rationale that OPM 
requires a 16-Bit file, and does an internal conversion to 16-Bit when fed files that 
are at 8-Bit. Apparently the OPM conversion routine has a problem. So that problem 
can be avoided by always feeding OPM with 16-Bit files. Within PS7 there is no 
apparent effect of a simple 8- to 16-Bit conversion so it is much better approach 
than resampling to solve the problem.

Doug Nielsen

Thanks Doug.

I guess then converting the images in PS& from 8 bits to 16 bits should do the trick.  I 
am saving the images in PS7 also @ 400ppi.

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Doug Nielsen" 
<douglasnielsen@e...> wrote:
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "luisvcool" <lvictoria@t...> 
> wrote:
> > Ok.  If i scan an image at 8 bits and before I print in on OPM I convert it to 16 
> > bits in PS7 and save the file,  will the resulting 16 bit image look better than if I 
had 
> > saved it at 8 bits and then printed it?
> > 
> > I'm confused.
> > 
> 
> 
> A couple of months ago I discovered that OPM prints from 8-Bit files at resolutions 
> under about 450 dpi displayed stair stepped diagonals - at least when examined 
with 
> a loupe. So, I did a series of prints to examine the 8-Bit vs 16-Bit treatment with 
> OPM. There was no question that feeding OPM with a 16-Bit file was better than 
with 
> an 8-Bit file. The effect was about the same as resampling an 8-Bit file up by a 
factor 
> of two. An 8-Bit file at 720 dpi produced about the same results as a 16-Bit file at 
> 360 dpi.
> 
> I don't know why this occurs, but I satisfied myself with the rationale that OPM 
> requires a 16-Bit file, and does an internal conversion to 16-Bit when fed files that 
> are at 8-Bit. Apparently the OPM conversion routine has a problem. So that 
problem 

> can be avoided by always feeding OPM with 16-Bit files. Within PS7 there is no 
> apparent effect of a simple 8- to 16-Bit conversion so it is much better approach 
> than resampling to solve the problem.
> 
> Doug Nielsen

> Within PS7 there is no 
> apparent effect of a simple 8- to 16-Bit conversion so it is much
better approach 
> than resampling to solve the problem.

I assume you're running OSX since you're running PS7 ?
How do you run OPM, under OSX ?  OPM is OS9-only right ?
So you just let Classic mode start up ?   Does this work ok ?

Thanks,
John 'Thinking of  Switching to OSX' Eyles

I run OPM in Classic Mode from 10.2.6.  I print on my 2200 one image at a time - 
after I print an image I quit OPM and then launch it again to print another image.  I do 
this because sometimes OPM quits or when I use the blender, one of the profiles 
"locks up" and an error message comes up.

So far (1 month), I have printed by B&W photographs using OPM on 10.2.6 (Classic 
mode) and I am very happy.  I only have the Epson Enhanced Matte profile the Carl 
Schofield so gracefully donated.  I wish I had profiles for Epson Velvet Fine Art and 
Epson Watercolor.

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "johngeyles" <jge@c...> 
wrote:

> > Within PS7 there is no 
> > apparent effect of a simple 8- to 16-Bit conversion so it is much
> better approach 
> > than resampling to solve the problem.
> 
> I assume you're running OSX since you're running PS7 ?
> How do you run OPM, under OSX ?  OPM is OS9-only right ?
> So you just let Classic mode start up ?   Does this work ok ?
> 
> Thanks,
> John 'Thinking of  Switching to OSX' Eyles

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, 
"johngeyles" <jge@c...> wrote:
> > Within PS7 there is no 
> > apparent effect of a simple 8- to 16-Bit conversion so it is 
much
> better approach 
> > than resampling to solve the problem.
> 
> I assume you're running OSX since you're running PS7 ?
> How do you run OPM, under OSX ?  

John,
Photoshop 7 is perfectly happy running with OS 9. I've been 
using PC 7.01 for nearly a year with OS 9.2.2 and only lately have 
upgraded to OS X. In fact, I recall some claims that PS runs 
better (faster) with OS 9 than with X.

Phil