I am using slide film in a Canon EOS 1V and I recently discovered that some of my pictures turn out to have a white stripe on top of the frame, e.g. in these ones:

enter image description here enter image description here

What I find weird is that only some pictures do have that stripe, while others turn out perfectly fine.

  • I thought it could be the sealing, but taken that it occurs so unregularly I don't think this is the issue.
  • I also don't think it is the shutter, because if it was, wouldn't the white stripe be more parallel to the border?
  • It's also not some stain or anything from the devloping process - it can't be rubbed off etc.
  • The stripe shows on the slides as well, so it's not due to the scanning either.

What could be the reason and what can I do to solve it?

  • Are your slides "loose" or mounted in slide holders? – Michael C Jun 4 '18 at 22:25
  • @MichaelClark they’re loose, not mounted... does that make any difference? – user74600 Jun 4 '18 at 22:27
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    Well, if they are mounted some of the slides could be slightly tilted in the holders, and the line may be present in all of them but only visible in some of them, with the edge on that side covered up by the holder in the others. – Michael C Jun 4 '18 at 22:52
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    How long are the exposures for the affected images? – Michael C Jun 4 '18 at 23:22

I also don't think it is the shutter, because if it was, wouldn't the white stripe be more parallel to the border?

Shutter issues don't always manifest themselves with light bands exactly parallel to the edge of the frame. If the second curtain is sticking slightly on one side of the bottom of the film plane (top of the inverted image) before closing, it could be at a slight angle before it finally closes.

That's what this looks like to me.

If the affected images are fairly long exposures, it's also possible that you have light leaking through the viewfinder and around the edge of the mirror which should be totally cover the focusing screen in the top of the light box. But that doesn't usually result in such a specific effect on the very edge of the frame. It's usually more of an overall fogging of the entire frame or more complex patterns caused by the leaking light bouncing around the various edges inside the camera's light box and off the back of the glass in the lens.

  • Thank you for your answer. That would explain why the issue only occurs on some images depending on the shutter speed. Stupid question, but do you maybe know whether the stripe will always stay on top of the picture if it actually is a shutter problem or is it possible that it might go right through the middle? – user74600 Jun 4 '18 at 22:29
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    Problems with a shutter curtain not closing properly will always extend to the edge of the frame. If there are gaps between the "leaves" of a shutter curtain it can show up in the middle of the frame. In an extreme case, an entire leaf can be missing. – Michael C Jun 4 '18 at 22:55

Light Diffraction

My suspicion is that the artifact you describe is caused by the diffraction of light around the mask that defines the edge of the frame inside the camera. This is normal and impossible to avoid completely. Most people never notice it because it is cropped out during printing, or hidden by slide mounts.

If you look closely, you will see that it occurs to some extent along all the borders. (Though it may be only a few pixels wide.) It will be more or less apparent depending on the scenes you are photographing. For instance, I would expect it to not be apparent in completely white or black frames.

If you look at the second sprocket scan in a window with a dark background, you can see a similar effect along the right border (but in this case, it is a scanning artifact). Perhaps someone else knows more definitively?

Loose Pressure Plate?

The effects of diffraction may be worsened if the film is not held completely flat. You can look at the pressure plate of the camera to see if this is the case.

Scanner Reflections

The first image you provide also shows what appear to be reflections outside the frame along the bright portions of the top and bottom borders. I think these were produced during scanning, though they could be from the camera as well.

The current scans with sprocket holes are at too low resolution to evaluate for these reflections. Higher resolution scans that include the sprocket holes would be helpful.

Shutter Issues?

Another answer states that a malfunctioning shutter might cause such a problem. I doubt this is the case, but if you're interested, you can see the shutter of a DSLR in action YouTube: Inside a Camera at 10,000fps

Shutter problems can be ruled out by exposing images independently of the shutter. This can be done by covering the lens with several layers of thick black cloth. Then expose the film by removing the cloth while the camera is in bulb mode. Replace the cloth before closing the camera shutter. A tripod and neutral density filter would be helpful.

Take an entire roll of photos this way. If even just one image shows the white line, it is definitely not caused by the camera's shutter. However, not seeing the white line in any images does not prove there is a shutter problem.

Since this is an unusual way to expose film nowadays, you might get some interesting photos in the process.

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