Re: Gum tonal range (was Miracle size for gum)
I don't think gum has a nonlinear transfer function; AFAIK, on contrary, dichromate processes have a pretty linear transfer function (as long as the dichromate strength isn't at the extremes = not excessively weak/strong), hence the non-linear tones in the resulting print. Our negatives are not linear in any sense, therefore, since dichromate processes are linear (or much linear when compared to the "literal" processes - if you like), the translation of non-linear negative densities to print densities are non-linear too. Said that, it should be noted that dichromate processes are pretty high contrast in the highlights. So when thinking the transfer function as a single entity, it's like a having a stepped / double character; almost having one inclination in the shadows and midtones, another in the highlights... (Hoping not being too complex/cryptic.) Regards, Loris. 2009/10/12 etienne garbaux <photographeur@nerdshack.com>: > ... nonlinear transfer function of gum ...
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