[pure-silver] Re: Adding Pot Bromife to PC-TEA
- From: Jordan Wosnick <jwosnick@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Tue, 11 Jan 2005 12:24:50 -0500
Ryuji Suzuki wrote:
> Using glycols as the solvent for stock solutions may prolong the shelf
> life of ascorbate developers, but it offers nothing to alleviate other
> problems that are sporadically reported. The sudden death without
> color change. No one really knows what causes it, but I strongly
> suspect that it is related to redox catalysis by minute amount of
> impurities from chemical stocks, water supply, and stuff that comes
> out of the film, reels, tanks, apparatuses, etc.
>
> We shouldn't forget about this problem.
Your hypothesis seems very reasonable. I was recently reading that
one of the major organic chemistry 'discoveries' of 2004 (a
palladium-catalyst-free microwave-induced Suzuki reaction,
ironically :) has been retracted -- it turns out that a nearly
undetectable amount of palladium salt contaminating a batch of
reagent grade sodium carbonate was the real catalyst.
It seems like ascorbate developers are particularly susceptible to
this. Water quality is probably an issue too -- iron everywhere!
Jordan
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