Re: Water and gum coating

From: "Christina Z. Anderson" <zphoto@uslink.net>
Subject: Re: Water and gum coating
Date: Tue, 18 May 2004 20:42:38 -0500

> The myth is in all gum books, passed along for generations--e.g. coat
> paper in room light as it is not sensitive until dry, but dry it in the
> dark, blah blah blah.

Well, I was more interested in the rationale behind that thought, but
that's ok for now.

> I mean, I coat *and* dry my paper in room light, so it doesn't make
> any difference to me one way or another, but all you have to do is
> stick a wet coated paper under UV light for a brief moment to see
> that it immediately exposes.

I see, but the the relation between wet sensitivity and dry
sensitivity varies with the pH... so, it is possible that in some
cases wet material is much less sensitive (in relation to dry
sensitivity) than what you have. I think some material was purposely
formulated to get that effect. It might be that the words got
separated from substance and spread around... it happens in silver
gelatin darkroom books as well.

Anyway, after all these stuff, what I'm more interested in in the
future is not the exact structure of chromium in gum, but a printing
process that does not use silver or chromium or iron, and the process
that may be very slow but can use visible light instead of UV
light. Is there anything like that now? (kinda like the sensitizer for
screen printing but not quite)

--
Ryuji Suzuki
"You have to realize that junk is not the problem in and of itself.
Junk is the symptom, not the problem."
(Bob Dylan 1971; source: No Direction Home by Robert Shelton)