I went out yesterday lunchtime to shoot a batch of tests as I've been a little frustrated with some of my negatives. 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 9 minutes 30 seconds (scanned emulsion side up)
Developed for 12 minutes 30 seconds
Incidentally, when I scanned the negative emulsion side down, it was quite a bit darker than the other way round, and so I know to make sure to scan emulsion up.
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 developing time seems incredibly short considering I'm using 1:1 dilution. But it is exactly how I saw it, so that is good. Of course, I'm scanning negatives in, and my scanner hasn't been calibrated, so 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. I'd probably say looking at the actual 6'30" negative, it is probably the best out of them.
What I find most 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. Of course, I was shooting these over a period of roughly a minute/minute and a half (I was fairly quick in changing the film holders) so the light outside could easily, and quite possibly, might have changed.
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.
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