Pentax Spotmatic SP500 - possible light leak

[guitarsammy]

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)?

 

[Helios 1984]

Did you refreshed the seals of this camera?

 

[shutterfinger]

3 possibilities, the back hinge light seal is not installed correctly, the back latch side seal not installed correctly, or the sun was coming in from the side and reflected through the pentaprism onto the film. Hold the camera so that your hands block the side light from reaching the eyepeice to prevent this.
Film touching or near touching during development has a different look.

EDIT:
The Spotmatic series of cameras have a lever that protrudes into the light seal/back track between half way and three quarters the distance from the eyepiece and the takeup spool chamber. If the light seal was installed over it or is interfering with its movement will affect winding and or the film counter.

 

[paul ron]

and the rest of the roll has exactly the same leak?

if you orient that negative properly in the camera, it would be the top of the door leaking, not the bottom.

it can be a pin hole in the curtain although it would show as a smear on the neg.
it can ( and most probably) be a leak from the door seals.

inspect the door edges for any damage or gunny residue from teh seals?
check to see if the mating edges have any missing seals or are gummy or damaged?

Put a bright light in the mouth of the camera and see if the curtain has a leak?

Lens off--- Fire the camera in B to keep the shutter open during inspection....
then with the back closed and an eye tight in the lens opening....
use a bright light from outside the camera n go all the way around and in the VF to find the leak.

EDIT: shutterfinger noticed the tab on the door.... i see it in your picture, bottom left... that must be the source of the leak at that point.