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Re: Hypo Eliminators (was: Dichromate and the plate)
Dear Sil:
Does this mean a sodium carbonate (10%) solution used as a washing aid for pyro
negatives should not be used, because of potential harm to the image and/or
gelatine.
If so, is it possible to buffer a sodium carbonate solution to avert this harm,
and if so, what would be a suitable compound with which to do so?
Your advice is appreciated.
Joe Arkins
Sil Horwitz wrote:
> 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>>
> <silh@psa-photo.org>
> <webmaster@psa-photo.org>
> Sil Horwitz, FPSA
> Technical Editor, PSA Journal
> check out <http://www.psa-photo.org>
> personal page: http://home.earthlink.net/~silh/