----- Original Message ----- From: "Graham Hughes" <graham@xxxxxxxxxxxx> To: <pure-silver@xxxxxxxxxxxxx> Sent: Friday, May 27, 2005 2:34 PM Subject: [pure-silver] Re: AgfaPhoto Insolvency > On May 27, 2005, at 5:46, Claudio Bonavolta wrote: >> Not really good news from Agfa-Photo as they've announced >> insolvency. > > This is a real pity, and means I should make contingency > plans for > the stuff they make that I use. I can use Ryuji's DS-14 > and DS-15, > but I don't really know what's in Sistan. Does anyone on > the list > know how to make something like it? > > Graham > I know whats in Sistan but not its actual formula. Fuji makes a stabilizer called Ag Guard. Its evidently not the same substance as Sistan but serves the same purpose. Both are stabilizers for the image silver where toning is not desirable. Fuji did publish some limited research on Ag-Guard. It shows that its effective in preventing oxidation and sulfiding of the image but is not as effective as toning. Sistan is essentially Ammonium thiocyanate and a wetting agent. The wetting agent is one of the forms of Triton-X. Triton-X is a brand name covering several different types of wetting agent. There may be other stuff in it. Agfa has revised the instructions for Sistan a couple of times because an overdose of it can cause staining. Probably the most practical protective toner is a polysulfide toner like Kodak Brown Toner or Agfa Viradon. I don't think its possible to get image protection without some change in the appearance of the image but that will depend on the film or paper. Its not difficult to make a polysulfide toner. Kodaks toner formula T-8 is effective as a protective toner according to IPI and there are other formulas. Its possible that someone else has more definite information on making up a stabilizer. I would also be interested in actual formulas. --- Richard Knoppow Los Angeles, CA, USA dickburk@xxxxxxxxxxxxx ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.