I use pyrocat HD 1:100 or a little bit stronger (1:75-1:100 -my measurements arn't precise) for 20 minutes at room temp. It works really well for me at this. I also use d-76 (1:1) or x-tol (1:1) with this film and it also works really well. There seems to be only a minor difference with x-tol and d-76 (A little more contrast with x-tol).