Digital BW, The Print

I was hoping an accomplished, active wet darkroom person could 
provide some information.  I want to create some B&W profiles based 
on LAB spectrophotometer readings of neutral, selenium, sepia, 
platimun and warm silver prints.  Ideally, one would take a gorgeous 
print, then make a second print of a 21 or 26 step grayscale using 
the exact same exposure, processing etc.  (Or, take LAB readings at 4 
or 5 points in the print, approximating zones 1, 3, 5, 7, 8).

Armed with this information, it would be possible to approximate the 
coloration from shadows to highlights in a good profile for IJC/OPM 
or QTR.  Perhaps someone has even done something like this already.

I know the coloration is subjective and based on the preferences of 
the photographer, but I thought it might be a useful starting point.

Can anyone help, or does someone have data they have already 
accumulated that they can share?

If this happens and I manage to create great profiles from the data, 
I would be happy to share what I come up with.

Thanks, Lou

I for one would love to see the numbers from this exercise.

I took the approach of just measuring different areas on a selenium toned print that I 
thought was very nice. I was surprised to find the a,b values very consistent across the 
whole range. I tuned a QTR curve to match the values (don't have my notes here) and the 
prints look pretty similar. My curve doesn't add toner in the deep blacks so they may be 
slightly warm, but this is not terribly noticeable to me.

Costa

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "ldina" <lbdina@c...> wrote:

> 
> I was hoping an accomplished, active wet darkroom person could 
> provide some information.  I want to create some B&W profiles based 
> on LAB spectrophotometer readings of neutral, selenium, sepia, 
> platimun and warm silver prints.  Ideally, one would take a gorgeous 
> print, then make a second print of a 21 or 26 step grayscale using 
> the exact same exposure, processing etc.  (Or, take LAB readings at 4 
> or 5 points in the print, approximating zones 1, 3, 5, 7, 8).
> 
> Armed with this information, it would be possible to approximate the 
> coloration from shadows to highlights in a good profile for IJC/OPM 
> or QTR.  Perhaps someone has even done something like this already.
> 
> I know the coloration is subjective and based on the preferences of 
> the photographer, but I thought it might be a useful starting point.
> 
> Can anyone help, or does someone have data they have already 
> accumulated that they can share?
> 
> If this happens and I manage to create great profiles from the data, 
> I would be happy to share what I come up with.
> 
> Thanks, Lou

If anyone has some small, full range, high quality, wet silver prints 
(selenium, platinum, warm, neutral, sepia), but no spectrophotometer, 
I would be glad to do the readings and post the results for all.  If 
anyone wants to mail them to me, contact me off line at 
lbdina@....  Just another way to do it.  I'd gladly mail the 
prints back if desired.

Thanks,  Lou

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "ldina" 
<lbdina@c...> wrote:
> 
> I was hoping an accomplished, active wet darkroom person could 
> provide some information.  I want to create some B&W profiles based 
> on LAB spectrophotometer readings of neutral, selenium, sepia, 
> platimun and warm silver prints.  Ideally, one would take a 
gorgeous 
> print, then make a second print of a 21 or 26 step grayscale using 
> the exact same exposure, processing etc.  (Or, take LAB readings at 
4 
> or 5 points in the print, approximating zones 1, 3, 5, 7, 8).
> 
> Armed with this information, it would be possible to approximate 
the 
> coloration from shadows to highlights in a good profile for IJC/OPM 
> or QTR.  Perhaps someone has even done something like this already.
> 
> I know the coloration is subjective and based on the preferences of 
> the photographer, but I thought it might be a useful starting point.
> 
> Can anyone help, or does someone have data they have already 
> accumulated that they can share?
> 
> If this happens and I manage to create great profiles from the 
data, 

> I would be happy to share what I come up with.
> 
> Thanks, Lou