Pyrocatechin or Pyrogallol were used in commercial MQ developers by Ilford and also Kodak to extend the life as well in D&P developers.
Adding: In a 1941 BJP article on the modern uses of Pyro developers there's a section on the MQ developers like D75 and D75b which include Pyro. The Pyro acts as an oxygen absorber someting that had been know bu then for some time according to the article.
Last edited by Ian Grant; 05-24-2012 at 04:27 PM. Click to view previous post history.
Reason: adding much later