Re: LC-1 developer question
From: Richard Knoppow <email@example.com>
Subject: Re: LC-1 developer question
Date: Fri, 28 Mar 2008 02:55:29 -0700
> Thanks, this is the first real explanation of why there
> are problems dissolving Metol in sulfite solutions.
Generally speaking, I see a tendency that things related to
"know-how" are rarely described systematically in literature,
except for isolated anecdotal stories. They have little
scientific value, but they still cost a lot of research
work. Basically, these are the kind of things that stay
secret. Solvent system design is a very common problem that
arises in many branches of industrial chemistry (even the
design of liquid laundry detergents) but even then the
situation is as you see in photographic literature.
In terms of solvent system design, the most interesting
developer, in my mind, is HC-110. But at the same time, it's
my least favorite developer in terms of photographic
properties. That developer is a better substitute for D-19
than for D-76.
Ilfotec DD-X and T-MAX developers are in a different league in
terms of the solvent system.
Well, I just wanted to make an example that DMF
(dimethylformamide) is a very common solvent, very useful in
making a concentrated developer, widely used in many
application areas, and it is actually used in some
concentrated developer products. No intention to single out
one product---there may be others who use this solvent. It
may be that some products were formulated decades ago and
never got revised, and some of the compounds are never
replaced since then.
"Make something religious and people don't have to deal with it, they
can say it's irrelevant." (Bob Dylan, Biograph booklet, 1985)