From: Liam Lawless (lawless@ic24.net)
Date: 04/22/00-04:49:54 PM Z
HI,
Self-toning papers incorporated gold salts in the emulsion, whereas it seems
you're mainly asking about combined toning-fixing baths, about which a
paragraph from The Albumen & Salted Paper Book:
Gold toning, which had the endorsement of the most respected photographic
authorities and was certainly a good idea in principle, was often the fatal
flaw in otherwise good processing because of the manner in which it was
applied; when photographers mixed gold chloride and "hypo" together, in many
cases the acidity of the gold solution decomposed the sodium thiosulphate
and liberated sulfur, which ultimately caused the prints to fade. This
method of toning was known as the sel d'or method, and it was the most
widely used approach to gold toning in the decade 1850-1860. When the
solutions were fresh and the work properly done, the combined toning and
fixing of the sel d'or method occasionally produced prints of excellent
stability, but in ordinary practice the method had too many drawbacks and
was finally replaced at the end of the decade by the vastly superior
"separate" toning approach.
Alkaline gold toning also deposits more gold than in acid solution. Use any
commercial gold toner, but fix afterwards (if you have toned after fixing)
because toning reduces some of the silver to chloride, and because fixing
undoes any combination of the gold with the gelatin.
Liam
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