Re: was Miracle size for gum now tonal range
I don't think I told "I get a longer tonal range". What I told was: "I use / prefer negatives with longer DR", adding now: -to get the tonal range possible with the particular coating solution is able to give. Tonal range (as I understand it) is a function of the pigment and pigment concentration to my knowing. The negatives I use are printed with a color that gives me 14-15 steps with the 31-step tablet and 2A+1B trad. cyanotype (A being 20% and B being 8%, I recently switched to A 25% and B 12% but haven't used those negatives for gum yet. These need a more blocking color since 31-step table test prints indicate 16-17 steps...), therefore I assume my coating solutions are compatible with a negative with a density range of log 1.4. Maybe gum spectral sensitivity is way different than cyanotype, therefore the same negative (color) that reads log 1.4 for cyanotype translates to a lower figure for gum - I can't tell since I haven't checked that with a real (silver) negative. With gum, I left printing step tablets very early, exactly when I discovered that my cyanotype negatives are perfect for gum already. (My trials before - with lower DR negatives - were all inferior in terms of shadow detail compared to what I get with cyanotype negatives.) OTOH, I clearly remember posting here a Stouffer 31-step tablet gum (thalo blue) test print showing 16 discernible steps (including dmax and paper white) a couple of years ago. BTW, I do get some color change in the darkest parts (blacks) of the layer but not too much; it doesn't affect the midtones and highlights. Does that counts as dichromate stain due overexposure? Regards, Loris. 2009/10/10 Christina Z. Anderson <zphoto@montana.net>: > ... > You say that with weaker di and greater exposure you are getting a longer > tonal range--do you have a picture on the web of that comparison somewhere? > ...
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