[pure-silver] Re: Anti-oxident
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Wed, 18 May 2005 21:42:49 -0400 (EDT)
From: "John Black" <jblack@xxxxxxxxx>
Subject: [pure-silver] Anti-oxident
Date: Wed, 18 May 2005 12:14:23 -0400
> This query is for Ryuji (or anyone else that might know the answer):
> Might diethylhydroxylamine be used as an oxidation protector in B&W
> developers? I note it's use in RA4 and C41 chemistry in the same
> capacity.
Although hydroxylamines are most frequently claimed in color developer
patents, this type of compounds are often listed as a possible
preservative in many b&w developer patents as well, and there is
nothing particularly novel about it.
One problem with hydroxylamine compounds is its volatility and
odor. Despite this problem it is often used in color developers
because they can't contain much sulfite. N-disubstituted hydroxylamine
derivatives with alkyl, aryl, etc. groups are often used because they
act more slowly than sulfite, and they are less smelly than smaller
hydroxylamines.
I think those should work well for b&w applications with phenol
developing agents and phenylene(mono,di)amine agents. How well does it
work for ascorbate developers is another question. Another concern is
that hydroxylamines often contain small amount of ammonium compounds
as the impurity, which may accelerate development, affect the solvency
of the developer solution to enlarge the developed grain, or
both. When hydroxylamines are oxidized, they make free ammonium ion as
well.
I haven't tried this agent but I thought about it at some point and I
preferred sulfite over any hydroxylamine derivatives.
--
Ryuji Suzuki
"Keep a good head and always carry a light camera."
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