From: Darlington Media Group (postmaster@mediaworkshop.demon.co.uk)
Date: 12/03/00-06:13:30 AM Z
Hi John,
A technique that I have used in the past to clearg stubborn chrysotypes is
to use sodium dithionite.Try clearing your platinum print in a 3-5%
solution of sodium dithionite. However, be warned...sodium dithionite
produces a very offensive odour, similar to sodium metabisulphite (used for
sterilising wine bottles etc) so clear your print outside in the fresh air.
Make sure your print is washed well and free from previous clearing agents,
which would cause chemical cross contamination and note that a solution of
sodium dithionite has a very short working life of around fifteen minutes.
Also, it could be that the paper you are using is buffered with sodium
carbonate which reacts with ferric compounds to produce ochre, an insoluble
compound. Experiment with different papers to see if the yellow stain can
be avoided.
Hope this helps.
Tony McLean.
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