FP4 in a PhotoTherm

I am setting up a PhotoTherm processer to do cut film. I will be shooting FP4. The instructions are geared to TMax developer and show a development time of 3:30 minutes @ 75 F. I plan on using PyrocatHD in the Glycol base. I checked with PhotoTherm's tech supoort and there is no ploblem with this developer. I questioned them about the seeming low development time for FP4, which is about half of the Ilford recommended time. The gentlemen indicated that it was that the B&W processing is done at 75 F. In the instructions for the PyroCatHD it shows for rotory processing a base development time of 7:15 minutes @ 75 F. I am looking for a correct starting point to develop the FP4. Has any one got experience or insight they can share?

Jeff, I just started using a PhotoTherm processor myself and want to start using Pyrocat-M (the one developed using Metol and specifically created for rotary development). I am currently using the TMax developer diluted 1:4 per PhotoTherm's directions at 3' 30" for FP4 (rated at 64) and it's working great, but would like to get back to Pyrocat so let me know if you do any testing and I'll do the same.

I will be happy to post my findings and tests. In the Phototherm there will be no presoak. I don't know how that will effect things?? I will find out! Also I see that you rate the FP4 at 64 EI and process at the recommended time from Phototherm with FP4 at 125 EI. Did I read that correctly?

jeffzeitlin said:

I will find out! Also I see that you rate the FP4 at 64 EI and process at the recommended time from Phototherm with FP4 at 125 EI. Did I read that correctly?

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Yes, I found that the first negatives I shot were too thin for the alt process work I was doing, but that extra stopped just ran the tones up further and gave me the shadow detail I was looking for.