Re: Sistan Formula

As far as I know, there is no published formula for Sistan. If you see
a "formula" based on guesswork from MSDS, I would be very leery of
using it for various reasons. We know that the active ingredient of
Sistan is thiocyanate but in order for the effect to be optimal, the
amount is very critical; too much thiocyanate is badly harmful, and
too little is ineffective.

A better option is Fuji Ag Guard. This product uses a superior
compound (an organic thiol compound) which has a wider window of
effective dose. However, the solubility of this type of compound is
generally very small (Fuji made one that is reasonably soluble, but
still they cannot make highly concentrated stock like
Sistan). Availability of this product outside Japan is also limited.

If you want to use any homemade counterpart of these products, I can
tell you more about what I know about how these things work, but I'll
also have to tell you that you MUST test for efficacy of treatment, at
least by peroxide fuming test at high humidity condition. There are
some well known compounds that can be effective in protecting image in
one way but very detrimental in different ways in certain
conditions. This is the kind of things you want to be extra careful
when discussing image protecting agents.

The easiest way is to stick with well tested products/methods.

Ryuji

From: marc bruhat <m.bruhat@free.fr>
Subject: Sistan Formula
Date: Sat, 10 Dec 2005 11:30:55 +0100

> Dear list,
>
>
>
> I have been delighted to read again the list, having left it for more than five long years.
>
> Somebody remember me, especially because my bad English and also a little because I have organize the first alternative symposium with Paris, France, in 1995 (?).
>
> I am very annoyed.
>
> I continue my road of silver and platinum black and white printer, after having worked for the largest French photographers, like Helmut Newton, Henri Cartier Bresson, Robert Doisneau etc.
>
> All deaths, alas!
>
>
>
> AGFA let me know that they not delivered the SISTAN more.
>
> May be somebody among you knows the formula with sulphocyanide.
>
> I request your assistance, because I think that it is really the solution for the conservation very long duration vis-a-vis new pollution.
>
>
>
> Thank you by advance for information.
>
>
>
> best regards
>
>
>
> Marc Bruhat.
Received on Sat Dec 10 06:44:04 2005