This was posted in Usenet from some formulas translated from a German source. Calgon 1 N-hydroxyethyl-o-aminophenol 6 Pyrocatechin 10 Hydroquinone 4 Sodium sulfite anh 100 sodium carbonate anh 25 potassium bromide 1 water to 1 L I was surprised to see the Pyrocatechin listed. I recall using this many, many years back after getting a Porter's grab bag or something. I remember not being very enthused about my results at the time and found no reason to ever return to tuning it in. I hadn't thought about it having any stain at the time (but I wasn't at all aware of pyro/tanning solution back then, either).