At 06:52 AM 17/02/2005, Jerry wrote: ..........It is said that Metol and pyro are superadditive but I have not seen any >data confirming this. Even so the superadditivity ratio of Metol to >hydroquinone is around 1:3 or 1:4 and I would suspect that it would be >in the same range for pyro. In PMK the ratio is 1:20 which does not >appear to be optimum. Such a high ratio is what is usually evidenced by >Phenidone in superadditive combinations........................ Isn't the ratio of metol:pyrogallol in PMK 1:10? John S ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.