I'm assuming that the backing that was described above is the oil I've heard about...

Every once in a while at the lab I used to work for, someone would show up with this mystery film... They didn't know where they got it from, but would ask us to process it. We would flatly refuse. From WHAT I WAS TOLD, it has to be processed differently because this backing becomes like an oil in normal chemistry contaminating things.

Make sure you can get things processed before you invest in any specialized films...

joe