Re: (Drumroll): gum prints w curved vs uncurved negs (Re: How manygum layers (Re: ferri sesquichlorati)
Katherine, > (An offlist > correspondent thought I must be applying the curve to the negative > rather than the positive, but that's not the case). I can't speak for ChartThrob, as I've not tried it. But generally speaking, you want to curve the negative, not the positive. Have you tried making a test print with the curve applied to the negative? > Someone wrote a while back to say that when > they use PDN with tricolor gum, the print comes out too dark, and > wondered what they were doing wrong; the answer was something like, > "Oh, yeah, that's what always happens," the recommendation being > that the inquirer just play around with variables, I forget whether > it was pigment concentration or exposure, by trial and error until > they find something that works, using the same curves. If this is the case, they didn't correctly use PDN. I can tell you from experience that the only time my PDN'ed gum prints have been too dark, or too light, or too conrasty, or not enough contrast, etc. it's been a poorly calculated curve. Running through the calibration process again always solved the problem. >And then it > turns out that after all one doesn't use a different curve for > different pigments, as has been claimed here much in the past; one > just uses the same curve and varies the exposure (which kind of > messes with the idea that the curves are supposed to be based on a > standard printing time, doesn't it?). Again, incorrect use of PDN. Each pigment does "require" its own curve; this is especially aparent in curves for yellow pigments, where it doesn't follow the standard "s" shape that most others do. > So I'm inclined to think that there's not much difference between > what we're all doing; whatever kind of negative you start out with, > you still have to master printing gum, and no matter what kind of > negative you start out with, you're still going to be "fiddling with > it until you get what you want in the print." Well, mastery of process is a given, no matter what you're working on. But in my own experience, curves have made a tremendous difference. So I'm going to have to gently disagree with you there. Camden Hardy camden[at]hardyphotography[dot]net http://www.hardyphotography.net
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