So far, I have produced prints using substitutes for gum arabic and pigments, but only of
medium quality. I'm looking for help in understanding the variables of the process.
More specifically, I have been working the simplest of the gum techniques;
mixing sensitizer, colloid and pigment followed by exposure under a negative.
I am having trouble controlling the hardening reaction.. rather than see the
pigment differentially held to the page by hardened colloid I am seeing
the pigment overlayed more or less uniformly across the page on top of the
olive color of exposed ammonium dichromate.
My immediate question is "what conditions should I vary?". Gum techniques
are notoriously finicky, meaning the issue could be mechanical (e.g., in my
preparation and use of the media) or chemical (e.g., in my choice of
substitutes). I'd love to compare notes with someone who has broader
experience in gum printing (that could include a lot of people).
My second question is, "does anyone have experience with gum process substitutes, or
knowledge of gum printing at the chemical level?" I have a rather stale degree in chemistry
and have read easily available material on the topic. However, my experience to date
says it is time to talk with People In the Know.
Dan Shapiro