Preparing Negs for gum bichromate printing

Dwayne Sandall (sandall@cc.umanitoba.ca)
Fri, 26 Aug 1994 15:38:06 -0600

I have recently decided to go back to doing traditional (ie. chemical and
optical) photo manipulation, leaving the wonders of Photoshop alone for a
while. One of the techniques I am interested in is gum bichromate, which
has left me with a large number of questions.

ps. I have just started looking for printed reference material to
supplement a couple articles I clipped years ago, so the books may provide
the answers.

Anyways, on with the questions

1. Negatives: my understanding is that colour is introduced via the
different chemical washes. Now, do you need to produce four separate negs,
ie. as in four colour separations to produce the image, or is by merely
brushing in the appropriate solutions?

2. How and where do I get large negs done?, (most images will
probably start as 35 mm negs/chrome, although there may be some 2 1/2" negs
(if I can convince a friend to lend his gear:-) Is pmt an appropriate
means? The two articles I have seem to assume this part, like you just
happen to have 11x14 negs handy.

Thanks for your responses, and all my apologies if these are silly questions.

p.p.s. is there an FAQ for this list?

Dwayne Sandall
Advanced Visualization Laboratory
Faculty of Architecture
University of Manitoba, Canada
(204)474-6963 (fax)275-7198