I am trying to Bleach and redevelop impossible silver shade film to intensify and tone them
I have a number that I peeled to get the b/w transparency which I have bleached in ferricyanide/potassium bromide
then I redeveloped in multigrade developer which all works ok except that the emulsion starts to lift
Has anybody got a suggestion for how to fix the emulsion layer so it dose not lift leaving me free to redevelop/tone etc
You can try hardening the film before you bleach(a few ml Formalin per liter of water would do that), or you can try a different rehalogenating bleach. Any C41 or E6 bleach should work, just make sure it's not a BLIX. See (there was a url link here which no longer exists) for a recipe (you can leave out the Ammonium Nitrate).
Tetenal hardener is Alum based which means it needs pH lower than 5 to work. Since it is normally used together with fixer, the hardener alone will likely have very low pH. Too low a pH can also soften the gelatin, which means you may actually make the problem worse if you are not careful with this product.
Even if you get the pH up to 4.5 or so I still can't tell you whether it will completely solve your problem but it will be an important step in the right direction. Try it with a test clip before you commit a whole roll of film.
PhotoEngineer once gave a recipe for E6 final rinse which asked for a few ml of Formalin 37% per liter of final rinse. With your 10% Formalin you should use about 20 ml per liter hardener. Don't use 10% Formalin as it is likely too strong for hardening, and make sure you read the safety instructions before using Formalin.