Roll 168: Roll 166 showed uneven development and some folks commented that it could be due to bubbles in the development tank. Even though I tap the heck out of the tank, I rolled with this hypothesis as I didn't have a better one, so I went back to the Simma roller, and I redid the film curve, starting with Acros. I shot frames from -5 stops below normal exposure to +6 stops above normal exposure along with a blank frame so I can measure the film density above base + fog. I metered the film at ISO50, and if that speed had been accurate then the -4 frame should have given me a density of 0.1 (0.3 stops darker than base + fog). But it is the -4.5 frame that gives me a density of 0.1, so the film is half a stop faster than metered. Since my light meter works at 1/3 step ISO speeds, and I like round numbers, I will simply call this ISO50, and since the curve does not level off for ages, I think this is safe.
Recipe:
Develop: Rodinal, 1+75 = 12 mL + 900 mL, 12 min @ 20 C in Simma sine wave roller
Stop: Ilfostop 1+20, 10 inversions by hand
Fix: Ilford Rapid fixer, 1+4, 5 min @ 20 C in Simma since wave roller
