U of S | Mailing List Archive | alt-photo-process-l | RE: uncurve/curve comparison on Loris' website

RE: uncurve/curve comparison on Loris' website


(1) I agree. My suggestion was assuming Chales doesn't want to go back
to recalibrate each primary color individually but solve the problem
pragmatically -> still using those curves. He says that his calibrations
for each primary color is good -> if he does something wrong, that
should be the pigment concentration... I don't know if it's enough to
simply re-establish a new standart printing time when cutting back the
pigment amount, but I feel like that won't be enough (= probably curves
also will have to change). And if it's that way, then he'll need to go
back to the long / laborious process of recalibrate... I would
definitely try what I suggested and see if that gives satisfactory-to-me
results. If yes, I would never go back to recalibrate since I'm more
interested in making images instead of making images *in the absolutely
correct way*. (Don't take it like I'm not interested in the latter at
all, I just give more importance to be able to put my vision on

(2) Yes indeed. But since Charles said that the only way of getting
paper white with his printer (R1800) was using all inks grayscale
negatives, I simply trust him. AFAIK, R1800 are not the best in the
domain of UV blocking... That leaves him the only option of reducing the
ES of his coating solutions (where available), which translates to "use
less dichromate" and/or "use more pigment" in gum printing. Since we
already suspect that his pigment concentrations are higher than what is
needed, then using less dichromate looks like a sound advice to me.


-----Original Message-----
From: Don Bryant [mailto:dsbryant@bellsouth.net] 
Sent: Friday, September 28, 2007 3:05 PM
To: alt-photo-process-l@usask.ca
Subject: RE: uncurve/curve comparison on Loris' website


Charles if that also doesn't work, don't overlook my suggestion of a
levels / gamma adjustment channel before making separations (in
luminosity mode -> thanks Michael)...

(1) I have to say, IMO that I regard this as a poor approach to solving
the problem. Better to get the curves correct (if one is using curves).

BTW, what dichromate concentration are you using? You may try to use
less dichromate if you use saturated solutions. That way, you may
achieve paper white with colorized negatives (despite their DR being
lower compared to grayscale / all-inks negatives).

(2) You can achieve paper white with saturated dichromate using
colorized negatives.