[pure-silver] Re: AgfaPhoto Insolvency

----- 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 

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