The original formula was first published at www.unblinkingeye.com, and all subsequent modifcations to the formula made by me were posted to that site. Therefore, if there is such a thing as an official Pyrocat-HD formula it is the one you will find at Unblinkingeye.
Originally Posted by Bruce (Camclicker)
Even though I never exchanged any communicaitons with him on the subject I had long suspected that there was a strong family ressemblance between some of Barry Thornton's last developers, particulary Exactol, and Pyrocat-HD. One could easily see why, in that Exactol, like Pyrocat-HD, is based on pyrocatechin/phenidone and the recommended dilution for silver printing is 1:1:100 for both developers. Now that we know that Barry Thornton carried out a considerable amount of research into the Blackthorn modified Pyrocat-HD developer it seems quite reasonable to speculate that Exactol is to some degree derived from Pyrocat-HD, with modifications perhaps made by Thornton to lower the working pH. If Exactol ever gets back on the market I will perhaps try to obtain some and do a comparison of it with Pyrocat-HD.
Last edited by sanking; 02-16-2005 at 09:26 PM. Click to view previous post history.