Found out a roll of 35mm film has exactly one spot the pressure plate can scratch, and I learned it the hard way on a Canon AE-1 | Camera Repairers - HW Forums
Ever seen what a scratch looks like when it runs right through someone's kid's birthday pics? My buddy shot his daughter's whole party on an AE-1 and every single frame had this thin white line slicing through it, right in the same spot. Turns out a tiny burr on the pressure plate was doing it the whole time. He never noticed until he got the prints back and wanted to throw the camera off a bridge.