I have a roll of old NPZ 800 that was part of a handful of old, freezer-stored film I got with a camera. The leader is retracted almost all the way into the cassette (which is in the wrong canister), and there is a small piece of tape on the leader. My guess is the photographer who owned the camera shot part of the roll. I contacted him and asked, but he did not remember, and did not seem concerned about what might be on the roll. So I was going to do a clip test to see if it was partially used. I was wondering if I can use black and white developer and fixer for this.