For developing Ilford FP4+ in Pyrocat-HD, 1:1:100 dilution, I would suggest the following times as guides to being tests for your own conditions. The recommendations are for projection printing of silver gelatin papers, Grace #2 or VC Filter #2.

Development standards are: rotary processing in BTZS type tubes with gentle but constant agitation in water-bath, temperature 70 degrees F, pre-soak of 2-3 minutes.

Recommendation for Zone System

N-1 5:00 minutes
N 8:30 minutes
N+1 15:00 minutes


SBR 8 5:30
SBR 7 8:30
SBR 6 14:00

My testing shows that development times for the 1:1:100 dilution of Pyrocat-HD are only about 70% of PMK times, to reach the same CI. And with this paritcular film, Ilford FP4+, there will be about a 1/4 stop increase in effective film speed with Pyrocat-HD, as compared to PMK.