[Alt-photo] Palladium bleach

[Marek Matusz]

Bob This is an approximate recipe that I have used. I actually do not measure it carefully. Add to 1 liter of water: about 20 cc of 12% K2Cr2O7 solution, followed by about 2 grams of KBr, followed by about 10 cc of concentrated sulfuric acid (be careful as addition of concentrated sulfuric acid could cause local heating or boling). Bath to be used outside or with good ventilation as likely it involves bromine as a reactive agent. Use gloves and goggles, and handle all chemicals with care. Per-wet your print and immerse in the solution. Bleaching should follow in 2-5 minutes, rinse with water and follow with a bath of sulfite or metabisulfite to remove (neutralize) any residual oxidizers. Marek