From: Ryuji Suzuki -- JF7WEX (RSuzuki@MIT.EDU)
Date: 01/28/03-05:03:37 PM Z
From: Scott Wainer <smwbmp@starpower.net>
Subject: Re: gelatin hardener (was: paper for cyanotype or other alt processes)
Date: Tue, 28 Jan 2003 16:35:57 -0500
> Sorry for the confusion over the spelling of Glyoxal; I was feeling a bit
> dyslexic and did not use the spellcheck.
I thought your spell checker had dyslexia... :-)
(In fairness to dyxlexic people, I read very talented people are
more likely to have dislexia compared to average statistics.)
> I haven't had any problems keeping it since I displace the air (oxygen) in
> all liquid containers with nitrogen (non-reactive) that I get through a
> local bottled gas supplier. It is a nifty trick that I read about
> somewhere - I have kept a half-full bottle of concentrated Rodinal for over
> a year and it performed as if fresh.
I use VacuVin. It is designed for 750ml wine bottles but they are a
bit too tall to keep in my darkroom shelves. Glass bottles that accept
28-400 caps are usually compatible with VacuVin stopper and hand pump.
(Caveat: 28-400 indicates the outer size of the bottle, while VacuVin
stopper need to fit inside the bottle mouth. Since the bottle
thickness can vary, the above statement is not a guaranteed one.) The
largest bottle I found with this cap thread is a 500ml one. It's not
very convenient except for experimental developers in small
quantity. I think a short ABS (for Canadians) or PVC pipe of
appropriate diameter can be epoxy glued onto a larger cap for 2 liter
and 4 liter bottles after drilling a hole on the cap.
Nitrogen flush is also used among wine people. Some like to argue the
difference between vacuum and nitrogen. They make a great difference
when applied to a bottle that is fully enjoyed. 750ml of nitrogen or
750ml of nothing.
> As for other hardeners, there is Formaldehyde and Potassium, Chrome,
> or Ammonium Alum. I use hardeners only when absolutely necessary
> (which is to say almost never). Eliminate the hardener and use more
> care and you should not have any problems.
I plan to harden gelatin after exposure before development. This
excludes the use of alum hardeners.
Indeed, I have a long list of chemicals that can be used to harden
gelatin (and some plasticizers and surface friction reducers)
described by Hans Buschmann (an Agfa chemist?). But I think it is easy
for me to start off with what's known to work with paper and gelatin
people use for alternative processing. I'm doing silver gelatin but
the idea is the same.
Thanks for the answer!
-- Ryuji Suzuki "You're crazy man, there's no one here but me and my machines!" (Neil Young)
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