>>3496234Yeah in general light leaks happen in arbitrary spots. It depends on the scene you’re shooting, if it’s a low light scene the leak can be “masked” because not enough light is shining through it. Even in bright light, it can change depending which way you’re holding the camera and pointing it to the sun. If it’s pointed just the right way to the sun, light can leak in, while at a different angle it can’t.
Are you developing these yourself? Could it be an issue while loading the film? Lightleaks can happen not just in camera but also when you’re loading the film in the dev reel. Are you using a changing back or a darkroom?
I can’t see how it can be anything else than a lightleak. Faulty chemicals would have affected the whole roll in the same way. Obviously here it’s not the case cause the other frames (and more importantly the edge markings) are fine.
Incorrect loading (film clumping up on the reel) would give underdevelopment in those areas, i.e. they’d appear clear not black.
Lastly, some films on clear polyester base can give you “lightpiping”. I.e. when the leader is exposed to bright daylight (when loading in the camera for instance, or when you have the canister laying around with the leader out), due to diffraction, light travels through the polyester base and fogs part of the film that is still inside the canister. This would cause a lightleak in the first couple frames. Most modern films on polyester base have an (extra) antihalation layer on the back - which dissolves during development - to prevent this effect. Picrelated is an example of severe lightpiping, on a polyester base film that does *not* use a strong antihalation layer in the back. In most cases, just the first 2-4 frames would be fogged.
(Btw in your pic I can see the film is TriX, which is *not* polyester base. So at least on that roll, lightpiping is not the issue).
