The difference in stain with the addition of ascorbic acid between Hypercat and Pyrocat-HD is IMHO due to the difference in pH of the working solutions. Pyrocat-HD is working at a pH of about 10.9 while the pH of Hypercat is well over 12.

Bromide does not afffect stain, and the sulfite does in the Pyrocat-HD formula is far below the critical amount where it begins to reduce stain.


Quote Originally Posted by jdef
Hypercat works really well for me. Hypercat contains more ascorbic acid than you guys are using, but contains no sulfite or bromide, which I think makes the difference. There is certainly no loss of stain with Hypercat compared to Pyrocat HD. I think the Pyro-glycin-TEA developer I'm testing might also be useful for this kind of technique.