It not for figuring out exposure but for trying to figure out the developer. At least that's what I think I might be able to use it for. I found the stouffer website and I guess I could make a few photographs of the thing. Or maybe contact the thing onto the film? Or even stick it in the enlarger? Vary the developer until I get the widest range of results on the film.
The film isn't normal so any attempt to get normal results out of it will mean some experiments with the darkroom. While I could just stick the camera out the window being able to have some sort of reference would seem to be better. But I'm not sure-)