Re: LC-1 developer question
From: Richard Knoppow <dickburk@ix.netcom.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. -- Ryuji Suzuki "Make something religious and people don't have to deal with it, they can say it's irrelevant." (Bob Dylan, Biograph booklet, 1985)
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