From: Judy Seigel (jseigel@panix.com)
Date: 11/09/01-03:11:36 PM Z
On Fri, 9 Nov 2001, Katharine Thayer wrote:
>
> You misunderstood my remark.. I found his method amusing rather than
> instructive. Yes, there's some merit in his, but I prefer my own. A
> pound of dichromate in a pint bottle, for one thing, would hardly leave
> room for anything to be in solution.
I don't remember Zimmerman's dates, but the method of putting the
potassium dichromate in the bottle with as much water as possible then
topping off with more water as it ran low was in common use early in the
century and often advised in how-to articles.
I've never read of it done with ammonium dichromate, but I have a hunch
the am di didn't come into general use until later, and was also more
expensive, and, being stronger, you might not use a pound in a lifetime.
But I did do that with the k di (getting in the spirit of the times) for
maybe 6 months... I promise that the small difference in concentration
with changes in room temp aren't meaningful for our purposes -- we're no
way working to such close tolerances with our handcoated processes.
I gave it up purely because it made me uncomfortable, probably habit and
mental block, no problems that I noticed. After all, if we mix 200 cc of
sensitizer (my usual) at a time, it ages as we use it, sometimes over many
months -- that changes sensitivity too. If you keep working off "fresh"
solution, when you add water and more dissolves, the change with
temperature probably wouldn't be any greater, if as great.
About the Zimmerman process itself, there were comments in subsequent
articles of the period, most of them (as I recall) finding the faults, or
saying it failed. The fact that it seemed to get little if any following
is probably also a comment.
Re: projection exposure, some folks do that already. In those I know of,
however, the size is fairly small and the exposure long. (Not to mention
possible difficulties with re-register.) But I'd guess that as soon as we
find the perfect substrate for digital negs, we'll forget dreams of
projection gum.
Judy
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