In conjunction with a book I am writing on B&W film exposure and development, I have begun running some film/developer tests this week.

I discovered a program online which allows me to design graph paper for an H&D Curve with major lines every three squares. These, of course, correspond to stops (0.3) and third stops (0.1) used to calibrate log exposure against density (log opacity).

To reduce initial headaches, I am running the tests first with a Canon EOS using the same film emulsion as I shall finally test in sheet form. The rationale being that the electronic diaphragm and shutter of the EOS must be more accurate than the multiple springs in a view camera shutter. Also, the EOS shutter speeds, f-stops and ASA/ISO values are all in third stops, which makes them easier to plot on my custom graph paper. After the initial gross testing, I plan to do only fine tweaking with the sheet film to accommodate lens and bellows flare, different agitation methods and the different bd+f.

A problem arose when checking the light with my trusty Minolta IV incident meter, which I intended to also use with the LF tests. Never really noticed it before. But the meter’s ASA/ISO values are in third stops, the f-stops are in tenths and the indicated shutter speeds are in half stops. Made me crazy. Ever try to interpolate third stops into half stops in your head? As you are losing the light? While standing on arthritic knees?

Good news. I rediscovered the old Sekonic L-398M Studio Deluxe II meter. Nice big (pdf) picture of it on Sekonic’s website. The analog dial’s shutter speeds and diaphragm settings are both in third stops, as is the film speed. Just like the EOS and my nifty graph paper.

Even better news is that B&H is having some sort of sale this week. Twenty dollars off. Whoopee!

Ain’t low-tech swell?