Response to Thin Negatives from Film Speed Test

I just did this same test and discovered it's very easy to make mistakes! I left the camera on auto so it adjusted the shutter as I adjusted the aperture! Doh! Anyway, Zone 1 should be 4 stops down from Zone V. I'd change the E.I. in 1/3 stop increments to find .1 over B+F. The aperture is too coarse. Development won't affect it much. Use any gray or white target, since the meter will try to put it at Zone V. Be sure the target area is large enough on the film, as most densitometers have a several mm diameter reading aperture. Unless all your work is under floods, do the test in daylight. Meters don't have flat spectral response, nor does film, and it may make a significant difference in the result. The general opinion seems to be that Tri-X is in the 200 region, so your results aren't that strange.

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