So managed to shoot another batch of tests yesterday lunchtime with a wider brightness range. I metered at 8 seconds for the shadows, 1/30th (it might have been 1/15 though - need to check my notes which are at home) for the highlights in the window and exposed all sheets at ISO50.
I put the shadows in zone 3 and exposed for 1 second at f/16. The film I was using was Fomapan 100 and developed in a fresh batch of D76 at 1:1. I'm using continuous agitation with the BTZS tubes. The tempering bath was at 24c and I let the chemicals in their caps and the tubes with the film in them temper for about 10 minutes so they should have been well up to temperature.
These were all scanned essentially the same way in Epson Scan. I corrected the output settings to go from 0 to 255 and the input settings to stop shadow and highlight clipping, as explained by Ken Lee:
My screen is calibrated with a Spyder 3 Elite although it tends to run a little dark.
So here are the results:
Developed for 3 minutes 30 seconds
Developed for 6 minutes 30 seconds
Developed for 12 minutes 30 seconds
Developed for 9 minutes 30 seconds (scanned emulsion side up)
Incidentally, the 9 minute scan above was scanned emulsion side up, the following was the same negative scanned emulsion side down:
I think there's probably a bit to get out of this. I'm wondering if shooting Foma 100 at ISO 50 is possibly not right for me. I may start shooting it at ISO 80 or even box speed. To me, with all the above taken into consideration, 3:30 looks pretty much on the money but seems incredibly short considering I'm using 1:1 dilution. But it is exactly how I saw it, so that is good. But of course, I'm scanning in and it could easily be that the image looks crazy bright to the rest of you. When I look at the negative, it doesn't look particularly thin or thick, it looks pretty good.
What I also find strange is that the window seems brighter in the 3:30 scan than the rest where I'd have thought it would have been the other way round. I will double check I scanned in the right order when I get home. It certainly makes me wonder about scanning and its consistency.
My agitation of the tubes was pretty consistent I believe so a little surprised by the results. Anyway, if anyone has any comments, I'd definitely appreciate it!