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Re: Hypo Eliminators (was: Dichromate and the plate)
At 2000/03/26 07:34 PM +0100, Liam wrote:
>And a brief quote from Southworth & Bentley, on fixing, hardening, washing
>and drying: "Chemical hypo-eliminators are occasionally employed to replace
>or expedite washing. Some of these, e.g. caustic soda, act apparently by
>softening the gelatine and accelerating the diffusion of hypo." They also
>say, elsewhere, that Kodak HE-1 softens gelatin (or gelatine, as it was
>called in those days!)
Don't confuse "Hypo Eliminators" with "Wash Accellerators." Kodak now
specifically proscribes the HE series, noting they are harmful for
long-term storage of prints. Wash Accellerators are buffered and are only
very slightly alkaline. They are aids to washing; HE solutions actually
destroy hypo, and just incidentally, adversely affect gelatin. I'd keep
away from them, including that horrible example of "caustic soda" (sodium
hydroxide) which can do only harm.
<<sil>>
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Sil Horwitz, FPSA
Technical Editor, PSA Journal
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