I recently acquired an old Pentax SP500. I ran a roll of cheap colour film through it and, apart from a mirror that sticks when I use the meter (apparently a common problem), and a non-working shutter counter, it appeared to be functioning well. There were no apparent light leaks, but the mirror damper foam was in quite poor condition, so I decided to replace this and thought I may as well do the light seals, which were quite rotten in places, at the same time. I ordered a kit from a well-known (and very helpful) seller and went ahead and fitted it. I have since run a second reel of film (this time something a bit nicer, some Ilford FP4+) through the camera and developed at home. However, on about 8 or 9 of the 36 exposures, I’ve noticed some weird banding. It’s always in the same place on the affected frame (please see attached photo). I was wondering if anyone might be able to tell me if this looks like a light leak and, if so, is anyone able to tell me which seal might be the problem based on the position of the banding and its shape? An alternative theory I had is that it could have been a developing problem (perhaps I didn't get the film onto the reel properly and it stuck in places)?