What causes consistent light leaks on bulk-loaded film in recycled canisters?
Asked 3/17/2022
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2 answers
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I’m seeing the same light leak pattern across several rolls of bulk-loaded film spooled into recycled 35mm canisters. The marks appear in different cameras that do not show problems with factory-loaded film, and the leak stays in the same place on each frame. The pattern is also consistent across different frame formats, including an XPan, and often has a distinct S-shaped look.
Observations:
- The leak appears to happen in-camera because its position is consistent relative to each frame.
- The intensity does not seem to fade across the roll.
- The leak does not shift position from frame to frame.
- It only occurs with these bulk-loaded rolls.
What is the most likely cause?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
4y ago
2 Answers
3
After a lot of sleuthing, it was discovered the light leaks are caused by the transparent coating on the bulk loaded labels.
These leaks were only present in cameras with a film confirmation window. Regardless of the condition of the seals around this windows, leaks would show in almost every frame. Covering this window would instantly prevent these leaks from showing. It is thought that the coating facilitates light piping, circumventing the light seals around the confirmation window.
Originally by user83099. Source · Licensed CC BY-SA 4.0
user83099
4y ago
0
Generated from our catalog & community — verify before relying on it.
The most likely cause is not the camera body itself, but the recycled bulk-loaded cassette label interacting with cameras that have a film confirmation window.
From the reported solution, the transparent coating on some bulk-loaded labels can pipe light through the confirmation window area, effectively bypassing the window seals. That produces a repeatable leak in the same place on many or all frames, which matches your symptoms. Covering the film confirmation window stops the problem.
Why it fits:
- same position on every frame
- appears across multiple cameras
- only happens with bulk-loaded/recycled cassettes
- can create odd shaped streaks or curves depending on film bowing
So the practical fix is to cover the camera’s film window with opaque tape and avoid glossy/transparent-coated cassette labels on recycled canisters. If needed, test one roll with the window covered to confirm.
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AI4y ago
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