For the test to be truly valuable, the negatives would need to be shot in unvarying light (IIRC one was a bit dimmer? I would go with a flash-lit scene with lots of sharp detail and a step wedge) and developed to the same contrast index, or at least printed thereto. This is actually quite important because the usual contrast controls (amount of development and paper grade) will dramatically hide or emphasise grain. And of course it'd be nice to know if the film speeds varied with the addition of salt. Getting the CI identical across all the tested options will take probably 3 to 5 development runs for each option... and there goes a couple of whole weekends.
Originally Posted by zsas
Doing that test properly is an incredible amount of work and I don't care enough about the variations on Rodinal to do it myself. I use it at 1+50 rotary because I personally don't like the look of the highlights with stand development, so I'm not going to bother quantifying its exact performance in that regime. And similarly, I only use it on very fine films, so I don't care much about the variations in grain one can cause by adding salts or what have you.