You shouldn't need hardener with PMK, the tanning effect on the gelatin is supposed to make it very tough. I did manage to scratch a neg when I used to use a double bladed squeegee to wipe off the film. I gave that up the first time I scratched a good neg. Now, just a rinse in distilled water (my water in So. Calif. is terribly hard, full of crud) and Photo-flo.(posted 8975 days ago)