Hi Joe,
Metabisulfites used in clearing gum bichromate prints are to be used
with great care, as one would using formaldehyde. Even at a
concentration of 1% and used in trays, they irritate the respiratory
tract.
Proper ventilation or use of a fume hood is recommended by David
Scopik. To use them to wash off silver stains would be risky.
Rajul
On 22-Oct-05, at 2:26 PM, Joe Smigiel wrote:
>>>> zphoto@montana.net 10/21/05 9:41 AM >>>
>>> ...How do you clean silver nitrate stains off your
> sink/bathtub/hands?...<<
>
> Hi Chris,
>
> Although I can't remember the source, I read somewhere last week that
> silver nitrate stains could be removed removed from surfaces using a
> solution of sodium bisulfite. No solution strength was specified. I
> remember this because I have some sodium and potassium metabisulfite
> around and thought I'd give it a try since bisulfites have been
> discussed on this list in the past as a substitute for those two
> chemicals in reference to being used as a clearing agent of chromium
> stains in the gum bichromate process.
>
> Some of the old wetplate collodion books nonchalantly recommend
> removing
> silver nitrate stains from hands using a solution of the *extremely
> lethal* potassium cyanide fixing agent. Warning Will Robinson!
> Warning!!! From pre-OSHA times I quote Ellis ("The Photographic
> Instructor",1856, p. 13): "The nitrate of Silver Solution will stain
> the
> hands quite black when exposed to the light, but the stains may be
> easily removed by rubbing the spots with Cyanide of Potassium while the
> hands are wet, and afterwards wash in pure water." I wonder how many
> wetplate photographers dropped dead from doing so? Definitely not
> recommended! A situation where I'd prefer to live with the stain.
> (sic)
>
> A couple weeks ago after doing some wetplate I ended up with so much
> silver nitrate on my hands that they turned black and had a metallic
> shine to them. It wore off completely in about ten days, but until it
> did I got the oddest looks from store clerks whenever I went to pay
> them
> and receive change. I have found that cleaning glass plates with a
> whiting (calcium carbonate) and Everclear solution hastens the removal
> of the nitrate stains, I assume largely due to fine abrasion of the
> skin.
>
> Joe
>
Received on Sun Oct 23 09:13:46 2005
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