I have to fix a few things (clean the enlarger lens) and re-run the development time tests now that I have gotten more consistent at developing.
For my test I used the sensitometer to expose a sheet of TMY-2. I developed the film and read on the densitometer that I was close to ASA gradient so I put this negative in my enlarger and made a print of it.
Knowing which sensitometer step made the patches on the print, I graphed (with x-axis reversed) Log MCS and resulting print density.
Now all I need to do is convert my spotmeter readings to MCS. Then I need to figure out what other factors interfere with predictions.
I've attached something I did in Mathcad. It shows film plane exposure H from the metered exposure point down into the shadows in non flare and flare conditions. With flare you achieve the same exposure from a RD one stop further down into the shadows. Assuming these conditions, you can use the easier to control and interpret non flare conditions to calculate the film speed.
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