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Re: Selenium
At 2000/07/27 09:19 PM -0400, Judy wrote:
>Meanwhile, while we're on the subject, the books say that barium sulfide
>(I think that's the one) has same toning qualities as sodium sulfide
>without the stink... I bought some but somehow never tried it. Has anyone
>done that? Also I wonder if thiocarbamide (also with sulfur) would work
>with the VDB...????
1> Barium sulfide is VERY toxic. If you still have some, I'd recommend you
hide it somewhere. Look up the MSDS. I'd never get near the stuff. OTOH,
barium sulfate is completely inert, and is used in GI Xrays (given to the
patient as a soup - it is completely impervious to Xrays). Just think what
a little oxygen can do to change the characteristics of a compound. When I
was doing the research for my article on "A Study in Brown Toners" I did
try the barium sulfide, and decided it's so toxic, it has no redeeming
value. It does have an odor - all soluble sulfides have odors.
2> Thiocarbamide requires that the silver be in an active state and will
not react with black (or brown) silver. That's why it's normally used with
an oxidizer such as Potassium ferricyanide + bromide bleaches. I wouldn't
recommend it for VDB, but it might be an area for experimentation.
<<sil>>
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Sil Horwitz, FPSA
Technical Editor, PSA Journal
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