Originally Posted by
mikew
Hi Sizam. The only thing that I'd caution you about is to make sure that your testing consistently. Using a subject like a landscape or piece of architecture, the luminance of the scene can change quite dramatically in a matter of seconds and that can augment your results if you're comparing the same subject on different films. 1/2 stop difference in a particular shadow caused by the movement of the sun or a cloud or even a different camera position can be the difference between what you want and don't want.
That's also all assuming that you're exposing your film at the right film speed for the way you plan to process.
Personally, I've always tested film the Ansel Adams way by exposing a sheet of film with the bellows focused to infinity (at that focal length) to a non-textured surface illuminated to within +/- 1/10 stop. I turned a table upside down, taped a matte board to it, and moved it around until I got the right angle. I won't lie and say that it isn't a pain in the butt, but it's the best way I've found to determine film speed, even with flare, and other Zone System applications. I know it's not what you're looking to do, but exposing a given roll at a different film speed will make a big difference in comparison of tonal values and such.
My advice is to control as many of the variables as possible, otherwise comparisons can be quite useless. If you plan it all out you'll be fine.
Hope that helps a bit. Best of luck!
Mikew
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