72ml pure hyrdrogen peroxide (800ml of 9%, 600ml of 12%, etc)

9gm of pure citric acid

Fill up to 1000ml with distilled water.

Process at 40c (104f) (or as hot as you’re comfortable) for around 6 minutes (you might be able to get away with as short as 4 minutes). Be sure to wash the film really well before and after bleaching! Also, I’ve found it works best to shoot it about 1 stop faster than box speed.

It will turn the base a pale yellow color. This is how you know it’s working. The original negative image may not disappear depending on the reversal stock you use but it will be removed when you develop the second time. You’ll get a kinda sepia tone look in the end.

I have re-used my stock 3 times so far with no degredation in effect. Put in a UV-Safe container as peroxide will degrade in UV.

Currently tested films:

Orwo UN 54+

Fomapan R 100 (shot at 50iso)

WARNING! This stuff will burn your skin. Wear gloves! I foolishly didn’t the first time and was fingerprintless for a week afterwords.

Based off this rando PDF that may or may not exist in the future and tweaked to work better : https://www.filmlabs.org/docs/citric-hydrogen-peroxide-bleach.pdf