RE: Chrome Alum Gelatin hardener

Dear Clay,

Just a comment on hardening times. Aldehydes will harden faster than chromium alum.
Chromium alum will take up to one month to complete the hardening.

Philippe

-----Original Message-----
From: wcharmon@wt.net [mailto:wcharmon@wt.net]
Sent: Sunday, February 08, 2004 15:38
To: alt-photo-process-l@skyway.usask.ca
Subject: Chrome Alum Gelatin hardener

This question may be directed more at Sandy, if you are listening. I am in
full-blown psuedo-panic mode preparing my gumover portfolio for Fotofest, and
am thinking that my usual method of using glyoxal as my gelatin sizing
hardener is a little limiting for my new assembly line approach to printing,
since I have to hit the prints with gum fairly soon after the sizing step. The
glyoxal works fine when I do a handful of prints at a time and know that I am
going to get to them in a few days, but they always represent a ticking time-
bomb after I size the prints.

I did a web search and saw that you are using chrome alum as a non-yellowing
gelatin hardening agent for your carbon paper support. Since I have some of
that on hand, and I am having some problems getting formalin, I think that may
the best hardening agent to use.

 In your carbon book, you recommend 2g of chrome alum/1000ml of gelatin
solution. This seems like a very tiny amount. Is that about the right
proportion to get a 'medium' hard gelatin coat? And you recommend waiting
about 5 days for the hardening to fully occur. Is that still your experience?

Thanks,

clay
Received on Tue Feb 10 04:06:24 2004