What can cause a repeated horizontal line on 35mm film prints and scans?
Asked 4/6/2022
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2 answers
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I’m seeing a single horizontal discoloration/line across many frames from a 35mm Canon film camera. The line shows up both on lab scans and on the physical prints, and I’ve now seen a very similar line on two different rolls processed by different labs. On one slide roll, the line appears to be physically visible on the film when viewed at an angle; on the negative roll I can’t clearly see it on the film itself. Since it appears across multiple rolls and labs, could the camera be damaging the film, or is this more likely a processing issue such as rollers in the lab?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
4y ago
2 Answers
3
Because of the coloured negative base and the low contrast image, scratches may some times be easier to see on slide film and based on what you are describing, it sound like you simply have a scratch along the film. It does not have to be a different issue with the negatives.
Since you have seen the same issue on different films developed at different labs, it is also almost certain that you have some issue with the camera causing the problem. The base side of the film is facing backwards in the camera, that is towards the back door. I don't have an EOS 3000, but looking at online images of the opened camera, the camera seem to have on the inside of the door:
- On the film canister side, there is a silver coloured spring, which likely presses against and fixates the film canister. This spring should not come in contact with the film and therefore be irrelevant.
- On the takeup spool side, there is also what looks like a spring with a small rubber roller, which probably presses the wound up film against the takeup spool. This spring, and particularly the rubber roller, is however in the lower part of the camera. Since images are projected upside down on the film and you have the defect in the lower part of the image, this spring should not cause the problem, unless it is located differently in your camera compared to the pictures I found online.
- In the middle of the door, there is a pressure plate, which the film will move along and rub against. The pressure plate in the EOS 3000 seems to have what looks like ridges running horizontally.
I am pretty sure that there is something on this pressure plate causing the problem. It might be dirt, rust or a sharp edge, perhaps on one of these ridges. If you hold an affected film snippet upside down in the camera at the same level as it is usually transported, you will easier be able to determine at which height whatever is causing the scratch is sitting. You can also try to carefully move your finger along the relevant parts on the inside of the camera door to see if you sense a sharp edge or something alike.
Originally by user10009. Source · Licensed CC BY-SA 4.0
user10009
4y ago
0
Generated from our catalog & community — verify before relying on it.
A repeated line across many frames is usually caused by physical damage or pressure on the film, not by scanning alone. Since you’ve seen it on prints/scans from different labs, the camera is a strong suspect.
Two likely causes fit the answers:
- A scratch on the film — often from something inside the camera, especially along the film path or back door. On slide film, scratches can be easier to see directly.
- A pressure mark — film can be affected by pressure from the camera’s advance path or from dirty rollers in an automatic lab processor. A pressure line can show as a colored line in the final image.
Because the problem appears on multiple rolls from different labs, inspect the camera carefully first: the film rails, pressure plate, back door, and any springs/guides that touch the back/base side of the film. Look for dirt, burrs, or anything protruding that could run lengthwise along the film.
If possible, run a test roll after cleaning the camera, and compare the negatives/slides themselves before printing or scanning.
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