Originally Posted by sevo
Copex Pan microfilm. Probably 32 ISO at the best of times (approximately 20-30 years ago, I don't think they had that packaging beyond the early nineties at the very latest), when used for high contrast microfiches...
As there is enough of it for experiments, you should go by trial-and-error - using microfilm for pictorial results was difficult even when fresh, and the age will add another 50% variability to any number involved...
If you can track any down, the various tips-and-tricks for developing Kodak's High Contrast Copy, Tech Pan, or their Kodalith films for pictorial results would be a decent place to start the Trial-and-Terror experiments.