RE: solarized gums?
If you expose a step tablet with the same emulsion and equivalent
exposure time (I say equivalent because b+f densities of the step-tablet
and your negative substrate may be considerably different from each
other), you'll probably see that the tones will progress from dark to
light, then paper white (if you don't experience "stain" with the
emulsion / printing substrate you currently use) and tone again after a
couple (or more) steps...
Let's assume you're using a 21-step tablet and you got maximum black at
step 1 (= 1 x 0.15 = log 0.15 density) and paper white at step 8 (= 8 *
0.15 = log 1.20 density, 1.20 - 0.15 = log 1.05 density range) + you got
tonal inversion starting from step 11 and progressing up. This
indicates: for this particular emulsion (pigment/gum/sensitizer ratios),
you shouldn't use a negative with a density range more than log 1.05.
For digital negatives, log 1.05 density range will translate to
different colors and/or curve endpoints depending on printer model /
inks / negative substrate and method of making the negative (such as:
using black ink only, using all inks for a smoother grayscale negative,
using colorized negatives...) When I say color, I'm talking about the
color of the negative, I'm not talking about the color of the pigment in
If you manage to make a negative with a little bit less density (again,
that barely gives you paper white at specular highlights) you'll
probably free of tonal inversion. Limit the endpoint density using
Levels or Curves adjustment or change your negative color... (See books
by Mark Nelson and/or Dan Burkholder for detailed information on
colorized negatives. See also the articles in "Negatives and digital"
Hope this helps,
From: ilana swerdlin [mailto:email@example.com]
Sent: Wednesday, February 14, 2007 2:38 PM
Subject: RE: solarized gums?
Loris and Katharine,
Thanks! It worked-- gum is becoming incredibly fascinating to me. Both
of your advice and testing was helpful. Loris, one question when you say
'minimal fog/image'--do you mean to allow the coated paper access to a
small amount of light before exposing the negative? [or just that the
highlight should receive a very light, subtle, flat first coat?] And
also, when you say 'Use a negative density (color) that merely / barely
gives you white on the print', you mean make my negative overall darker?
Or make a negative--on the computer--with an ink other than black? Or do
you mean print my highlight with a light pigment?
I think the setup I have wants to have longer exposures. So when I tried
less pigment/gum after this advice, I needed longer exposure [Also
because I used an increased amount of dichromate] Anyway, the image was
slightly overexposed but I use the 'water spray' technique to manipulate
it, and I'm sure with subsequent layers my image will be rich [like I
want it to]
Gum is amazing. Thanks for the help.