Re: Liquid Emulsion Questions
From: Camden Hardy <email@example.com>
Subject: Re: Liquid Emulsion Questions
Date: Sat, 23 Sep 2006 12:28:58 -0600 (MDT)
> Have you considered using an alternative process like Van Dyke
> Brown? Depending on the process, you probably wouldn't need to
> worry about disposing the chemistry. Most of the chemistry I use
> can be dumped down the drain.
In small scale silver-gelatin processing, developer and fixer are the
concern for disposal. Phenidone-ascorbate type developers can be
readily decomposed in sewer system and environment and it is not a
problem in most areas with decent sewer system. Used fixer is a
problem because it contains silver (up to 1% in heavily used fixer),
which makes sludge in sewer system (when mixed with dirty water from
other sources---particularly that smells sulfur) and is burdensome to
the sewer treatment plant. Silver is a precious resource and should be
recovered anyway, so most institutional users collect exhausted
fixer. Switching to printing-out silver processes doesn't really
eliminate this problem because silver will be released to the
effluence water anyway.
Considering the problem of preparing 4' square negative for contact
printing with UV light, etc., silver-gelatin process is best suited
for large work. One clear advantage of silver-gelatin is photographic
speed and enlargeability.