This is something I've noticed for quite a while now. I've mentioned it to other folks who dev their own MF, and nobody seems to have noticed it. When I peel the tape (holding the film to the backing) from BW 120 film I can see a glow. It seems to be produced by the action of pulling the tape from the film. I haven't seen any evidence of fogging, and it's very faint. But I've looked for it hundreds of times, and it's always there. When I first saw it it totally freaked me out as I imagined the film being fogged, but as I said, no damage. It's still weird. Any body else seen this? Look for it.