Formula for copper based rehalogenating bleach
I am looking for a copper based bleach to use with second pass lith printing. I can't find my Tim Rudman lith book (ugh!) and I looked all over the web and I can't seem to find what I am looking for. I used some potassium ferricyanide bleach last night with some pretty interesting results, but I want to try a different bleach to see what the difference might be.
Thanks -- Mark
As a starter you could possibly use acidified Copper Sulphate and Potassium Bromide
Copper Sulphate (pentahydrate) 35g
Potassium Bromide 110g
Acetic acid (10%) 10ml
Water to 1 litre
Taken from page 99 of The Master Photographer's Lith Printing Course
Copper Sulphate 50 g
Sulphuric Acid 6.5 ml
Sodium Chloride 50 g
Water to 1 L
Dilute 1:9 for use
Thanks to both of you. This is exactly what I needed. I'll try it tomorrow evening!
A reader might note that Dr. Rudman's formula calls for concentrated sulphuric acid. If you are using the 48% sulfuric acid solution double the quantity to 13ml.
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