I got burned early on by letting my images go out to anyone, so I restricted them on flickr, and scan at a lower resolution. I'm happy to share with just about anyone who asks first and will acknowledge that it is my photo. I always let Sundance use anything they wanted for no fee, and Dell has been meticulous in maintaining originals and returning everything he borrowed.
I don't have photoshop, and perhaps scanning each piece of film is the answer. Each layer of film is .001" thick and when placed on top of each other, there is a certain level of distortion because of the thickness of the film and reflection from the underlying white paper. Proofing done these days from scans is done with actual wet color laid on top of each preceeding color thus approximating the actual printing process.
Fritz