Lately I've been struggling with determining a proper N development time for FP4 using PMK Pyro. I don't have access to a densitometer, so I'm using the visual method as described by Jerry Orabona (I can't post links here yet, but if you search for "zone system development test" on google it's the first result. I've also been using a film speed test he describes, which you can find by searching for "zone system film speed test"). I've shot a few rolls now and printed test strips, and the results I'm getting are a little hard to interpret.
For the test shots I've been shooting an evenly lit wall with no texture, out of focus, with a Hasselblad Sonnar 150mm, which was serviced recently. I'm using a Minolta spot meter and I've checked its readings against 3 35mm cameras' meters and it does seem to be accurate. I'm printing on Ilford MG RC paper, developed in Dektol 1+2, using a Beseler 65S color head diffusion enlarger at grade 2.5 (25 magenta)
First, everyone says the proper ISO rating for this combo is 80-100. When I shoot Zone I at 100 it prints at Zone II. One stop down from the indicated Zone I reading produces a black that is just distinct from the maximum black of the a blank frame (film base + fog). This would seem to indicated that my film proper rating is 200. But this seems rather unlikely. My question is, should I reject this and test for problems with the lens or with the metering? Or is it actually possible my rating is 200?
Second, I cannot get enough contrast out of the film. My latest test roll was developed at 70 degrees for 11 minutes and the frame showing a different shade than the paper white would be Zone 10, two stops off. This would indicate an approximate 30% increase in development time to about 14.5 minutes. Again, this seems so extreme that it makes me think I must be doing something wrong. I know that the green-yellow stain of the pyro acts as a continuously variable contrast filter on the higher values when working with variable contrast paper, so I'm wondering if that might be skewing my results? I thought maybe there would be inherent problems printing pyro negatives on variable contrast paper, but looking around at posts here and there it sounds like folks get good results with this combo. I just don't want to end up having to print everything at Grade 4 filtration to offset the stain.
Thanks very much for any suggestions.