From: Darryl Baird (dbaird@umflint.edu)
Date: 07/20/03-07:20:35 AM Z
James goes on to say in the next sentence that he has seen deterioration
in "group" toning exercises and thus suspects improper (too short)
washing is the culprit. Short answer, completely wash anything you want
to last.
--- My current obsession with toning (for the James' eggplant tone) has led to a few "observations": the strength of the sodium carbonate solution has a great deal to do with the speed, color and density of the final toned results -- I had a very weak 1 tsp S.C. to 32 oz. of Michigan water (high iron content) and the bleaching was quite minimal, so the tannic acid (14 gm to one liter) had a slight color effect... more like a slight purple/rose tone and not eggplant. Upon return to a stronger 10% solution of S.C., the print almost immediately turned a very deep rich eggplant color. I removed and washed for twenty minutes. Subsequent toning cycles using the 10% solution were problematic as the solution is too strong and bleaches too fast. In short, I've had better success with an initial weak S.C. bath, followed by a tannic acid bath, but the print can be returned to the S.C. for additional toning. Permanence is yet to be tested, but I'll try my morning sunlight window for a few weeks. -- Darryl ~ Loris Medici wrote: >According to Christopher James' ... <snip>... The author also states that the tannic acid toned cyanotypes he made 20 years ago show no signs of deterioration. > >
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