[alt-photo] Re: Gum printing: removing the dichromate altogether?
alt.list at albertonovo.it
Sat Mar 26 06:46:27 GMT 2011
a little OT:
> Glasses are often coloured with chromium and render it green so it is
> often added for wine bottle glass.
True that chromium is used to make emerald green glasses. Instead, for
bottles it is iron, usually already present as an impurity, making it green
or brown depending on reducing/oxidizing environment of the furnace.
Returning in topic:
some years ago I had a discussion with Katharine Tayer about chromium stain
in gum bichromate, the way to wash it out and chromium residue in the print.
I believe that she tried to contact a chemist for a chemical analysis of the
hardened gum arabic, but I don't know if she had any results back.
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