IMHO the best of the formulae is still the PMK developed by Gordon Hutchings in the early 1980s. The definitive work is called The Book of Pyro also by Hutchings. I have used this formula for 25 years and have never felt a reason to switch. If someone can prove to me there is a better pyro formula please do so.

The Book of Pyro and the pre-mixed A and B solutions are available from Bostick and Sullivan and The Photographer's Formulary.

steve simmons