Light leak/ development issue or something else?

[Don_ih]

The thing to do is shoot some more film and see if it happens again. Doesn't need to be a full roll. 3 or 4 frames outside in the sunshine will do.

I don't think it's possible that could have been caused by the tank, the developer, the reel, bending the film, the cassette, or anything outside the camera.

 

[robonfilm]

The thing to do is shoot some more film and see if it happens again

Yes, that's what I'll do I think. I'm always scared developing only parts of the roll as I'm afraid to cut in the wrong place!

 

[grain elevator]

I would consider just hoping it goes away without changing anything a waste of film. I'd first renew the light seals if they're old anyway to eliminate one variable. It's cheap and easy.

 

[robonfilm]

I would consider just hoping it goes away without changing anything a waste of film. I'd first renew the light seals if they're old anyway to eliminate one variable. It's cheap and easy.

Agreed. I changed the hinge seals before loading a roll of film. I'm really hoping the problem isn't related to the camera

 

[koraks]

I'm always scared developing only parts of the roll as I'm afraid to cut in the wrong place!

You can split a roll in half in the dark. Tape the leader of a new roll of film to the spool on a used cassette. Assemble the used cassette. Then with the lights off, pull out all the film from the new roll, then find the middle of the film. Cut it and spool the film into each cassette manually, leaving only a leader sticking out.
You can repeat this process to cut the roll into quarters.

I agree testing with more film should be done to determine whether it's an in-camera defect. I'm pretty sure it is; the question is what the exact nature is of it. @Don_ih's arguments make good sense and I think the back-and forth between him and me illustrates that it's not a straightforward situation.

 

[robonfilm]

You can split a roll in half in the dark. Tape the leader of a new roll of film to the spool on a used cassette. Assemble the used cassette. Then with the lights off, pull out all the film from the new roll, then find the middle of the film. Cut it and spool the film into each cassette manually, leaving only a leader sticking out.
You can repeat this process to cut the roll into quarters.

I agree testing with more film should be done to determine whether it's an in-camera defect. I'm pretty sure it is; the question is what the exact nature is of it. @Don_ih's arguments make good sense and I think the back-and forth between him and me illustrates that it's not a straightforward situation.

As always thanks to all for the precious advice, I’ll try your method and develop some more film in the next couple of days.
I’ll let you know the result if you’re interested.

If anybody has other ideas I’m still following this thread, so more than welcome to answer again here.

 

[MattKing]

I would consider just hoping it goes away without changing anything a waste of film. I'd first renew the light seals if they're old anyway to eliminate one variable. It's cheap and easy.

Agreed. I changed the hinge seals before loading a roll of film. I'm really hoping the problem isn't related to the camera

This is an important clue.
A recent change in hinge seals + a light leak which exposes down the centre of the film leads to the conclusion that the new seals aren't stopping light, they are encouraging it!
I'd be willing to bet there is a hole in the seals near the take-up or, less likely, the feed side.
I don't think it is the shutter - due to how even the exposure is across both the frames and in the space between them.

 

[robonfilm]

This is an important clue.
A recent change in hinge seals + a light leak which exposes down the centre of the film leads to the conclusion that the new seals aren't stopping light, they are encouraging it!
I'd be willing to bet there is a hole in the seals near the take-up or, less likely, the feed side.
I don't think it is the shutter - due to how even the exposure is across both the frames and in the space between them.

I hope you are right! I’ll see if the new hinge seals I installed make any difference.

No apparent hole was visible in the old ones I removed, but I figured that changing them wouldn’t hurt because they were the only ones I hadn’t already renewed.

If the shutter is the culprit surely this next roll will have a leak in the same spot as this one.

 

[robonfilm]

@Don_ih @koraks @MattKing I developed a few more frames after changing the hinge seal. Unfortunately, the problem seems to be still there (although less evidently).

I further inspected the shutter by locking the mirror up and pointing a strong light in the lens mount. From behind, when advancing the film, you can kind of see a very very small VERTICAL line of light between the curtains (see photo, sorry for the poor quality but it is over the capabilities of my phone's camera). I don't know if this little amount of light is within tolerance.
Anyway, the mark on the negatives is horizontal, so I don't see how it can be the cause of a vertical leak.

Also, the light seems to originate from the shutter curtains non perfectly overlapping rather than from an actual gap between them.
If that's the problem, will it be fixed by adequately tuning the shutter by a technician or is the shutter faulty and need to be replaced?

Thank to all that will take the time to read and answer.

 

[MattKing]

Anyway, the mark on the negatives is horizontal, so I don't see how it can be the cause of a vertical leak.

Don't forget that the film moves horizontally when you wind it.

 

[koraks]

I don't know if this little amount of light is within tolerance.

I don't think there should be any light falling through the closed shutter.

Anyway, the mark on the negatives is horizontal, so I don't see how it can be the cause of a vertical leak.

You mention that this happens as you transport the film. So as @MattKing points out, the film moves along this slit.

I don't know whether this is the (only) source of the problem. I also don't know what the best course of action is - whether this shutter can be fixed, and whether it's necessary to begin with.

 

[robonfilm]

Don't forget that the film moves horizontally when you wind it.

True, didn’t think of that.

I also don't know what the best course of action is - whether this shutter can be fixed, and whether it's necessary to begin with.

Do you know of a user who knows about repairing 35mm cameras?

 

[MattKing]

Do you know of a user who knows about repairing 35mm cameras?

I'll take this as a prompt to move this thread to the Camera Repair sub-forum.

 

[robonfilm]

I'll take this as a prompt to move this thread to the Camera Repair sub-forum.

Sure, much appreciated!

 

[koraks]

Do you know of a user who knows about repairing 35mm cameras?

Oh yea, @Andreas Thaler comes to mind. Have a look here: https://www.photrio.com/forum/threa...0s-repair-projects-and-recommendations.208573

 

[robonfilm]

Oh yea, @Andreas Thaler comes to mind. Have a look here: https://www.photrio.com/forum/threa...0s-repair-projects-and-recommendations.208573

Awesome material, thanks for sharing! Unfortunately it doesn't include anything about my beloved F-1 old.

 

[koraks]

Unfortunately it doesn't include anything about my beloved F-1 old.

Not yet, but Andreas has an impressive queue of cameras waiting to be worked on. He may also have some illustrations or links to materials that are relevant to your case. I'd recommend getting in touch with him.

 

[Don_ih]

Yes, that tiny slit would make a band of density exactly like what you're getting in your photos. If the camera was serviced, that should have been caught.

 

[Sharktooth]

If there's a slit in the shutter that's occurring during winding then you could put a lens cap over the lens while winding. That might explain why I couple of shots didn't seem to be affected in your original sample. Try winding every other frame with the lens cap on to isolate that issue.

For hinge leaks, you can tape over the hinges after loading the film. If you don't have leaks with taped hinges then you know your hinge seals are the problem.

I'd combine both in your next test roll.

 

[Andreas Thaler]

Unfortunately it doesn't include anything about my beloved F-1 old.

Unfortunately, I have no experience with repairing the Canon F-1, but there is a lot of information on the web, e.g.:

Canon F-1 Repair Article

Article from Camera Craftsman

learncamerarepair.com

https://phsc.ca/repair/Canon/canon_camera_f1.pdf

 

[robonfilm]

Thanks! I decided to take the camera back to the shop that performed the CLA. I’ll update the thread once the technician has finished working on it.

 

[Sirius Glass]

Thanks! I decided to take the camera back to the shop that performed the CLA. I’ll update the thread once the technician has finished working on it.

Tell us the outcome, please?

 

[robonfilm]

Hi, I took the camera back to the technician, but unfortunately, the issue still seems to be there. To be fair, the gap between the curtains seems to have been reduced, but it still affects the pictures by causing light leaks.

In you opinions is there any way to bend titanium shutter curtains back together?

 

[Andreas Thaler]

In you opinions is there any way to bend titanium shutter curtains back together?

In my opinion, no chance.

 

[Don_ih]

In you opinions is there any way to bend titanium shutter curtains back together?

You can try gently poking them with your finger, right at the point of overlap. You have nothing to lose. But pushing too hard will push the curtain out.

The light leak was probably caused by someone accidentally pushing on the curtain while loading film ... or while doing a cla....