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Scratch on Footage


Josh Kuzo

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Hi Everyone,

I'm trying to diagnose an issue that came back from the lab. Looks like a double sided curves scratch. It lingers on the second half of the roll and then the full next roll of the same magazine. It doesn't appear on the other two mag's rolls shot in between. Is this a mag issue or a coincidentally load issue? Arriflex SR3.

Thanks.

Screenshot_20240918-082830 (1).jpg

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That's frustrating. I've never had that happen to me. Hope I never do.

Perhaps these could be what they call 'cinch' marks which can occur when the end of the film on a wound spool is pulled too tightly. But really, I don't know what the scratches might be. If you find out, please let us know.

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2 hours ago, Jon O'Brien said:

That's frustrating. I've never had that happen to me. Hope I never do.

Perhaps these could be what they call 'cinch' marks which can occur when the end of the film on a wound spool is pulled too tightly. But really, I don't know what the scratches might be. If you find out, please let us know.

Thanks Jon. I'm definitely hoping to get some answers. I had this happen two years ago to a roll (the example picture) and now again. I'm trying to imagine how it could happen, just being in the image itself and not (visibly) connecting to the top or bottom of the frame. Are you saying it could've happened on the uptake side from the film not having enough slack to the collapsible core?

I saw that this person ran into the same issue and was also using an SR3.

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So the curved scratch is identical in every frame?

Does it move or change shape? It’s hard to diagnose anything from a single frame.

Generally camera scratches are very repetitive, due the nature of the machine. They are normally vertical, since that’s the only direction the film moves. The only exception might be where the film bends and twists between sprocket rollers and pressure plate, but the mags are designed to only touch the edges of the film even if the loop slips and film hits the mag wall. 

Cinch marks from tightening a dirty roll will be random, and not limited to the frame, so it’s not that if this is repetitive.

If you’re certain it came from the one mag, it might be worth removing the mag pressure plate assembly (2 screws) and checking the film path inside for film chips or something. You could also do a quick scratch test by running a few feet of clean film through and examining it.

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3 minutes ago, Dom Jaeger said:

So the curved scratch is identical in every frame?

Does it move or change shape? It’s hard to diagnose anything from a single frame.

Generally camera scratches are very repetitive, due the nature of the machine. They are normally vertical, since that’s the only direction the film moves. The only exception might be where the film bends and twists between sprocket rollers and pressure plate, but the mags are designed to only touch the edges of the film even if the loop slips and film hits the mag wall. 

Cinch marks from tightening a dirty roll will be random, and not limited to the frame, so it’s not that if this is repetitive.

If you’re certain it came from the one mag, it might be worth removing the mag pressure plate assembly (2 screws) and checking the film path inside for film chips or something. You could also do a quick scratch test by running a few feet of clean film through and examining it.

I'll get you a video clip to help diagnose!

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13 minutes ago, Dom Jaeger said:

So the curved scratch is identical in every frame?

Does it move or change shape? It’s hard to diagnose anything from a single frame.

Generally camera scratches are very repetitive, due the nature of the machine. They are normally vertical, since that’s the only direction the film moves. The only exception might be where the film bends and twists between sprocket rollers and pressure plate, but the mags are designed to only touch the edges of the film even if the loop slips and film hits the mag wall. 

Cinch marks from tightening a dirty roll will be random, and not limited to the frame, so it’s not that if this is repetitive.

If you’re certain it came from the one mag, it might be worth removing the mag pressure plate assembly (2 screws) and checking the film path inside for film chips or something. You could also do a quick scratch test by running a few feet of clean film through and examining it.

Here's some video with the artifact. I'm positive it only happened to footage from Mag 1, that's my only saving grace in diagnosing this, and subsequently trying to fix this in post...

 

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Yes, could be something sticking out in the path of the film where the film disappears into the slot, to or from the pressure plate. The scratch is consistent and hardly moves. Not cinch marks since they would be random.

But since the scratches hold fairly steady and are consistent it seems to me they might be being made at some point within the loop, as the film is being held steady for the exposure.

Edited by Jon O'Brien
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Hm, I think I've found my missing emulsion as this collection of dust at the bottom?

Otherwise I wonder if it's actually not a scratch but an unwanted optical reflection somewhere inside?

 @Dom Jaeger I couldn't find anything obvious behind the pressure plate assembly. I included the pic but obviously there's many more angles to be covered for full diagnosis. 

1000013522.jpg

1000013530.jpg

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So this is a "tap" scratch in my opinion, the film is tapping something mid frame. Usually this is caused by the loop tapping something, either upper or lower. It's for sure emulsion side. That "dust" is absolutely emulsion. So start looking at your loop size. Are you properly using the film holders on the pressure plate? Check the screws that hold the guides inside the magazine (picture above) and make sure there is nothing that could touch the film. 

Edited by Tyler Purcell
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2 hours ago, Josh Kuzo said:

Hm, I think I've found my missing emulsion as this collection of dust at the bottom?

Otherwise I wonder if it's actually not a scratch but an unwanted optical reflection somewhere inside?

 @Dom Jaeger I couldn't find anything obvious behind the pressure plate assembly. I included the pic but obviously there's many more angles to be covered for full diagnosis. 

1000013522.jpg

1000013530.jpg

Ah, so it's not actually a scratch on the film? If it's a scratch, you will see the physical scratch on the surface of the film if you hold it up to the light at the right angle. Check it with a loupe/hand lens in a good light. But you think it might be an optical effect? That's a whole different kettle of fish. It holds steady and it's not just a general 'burn' of the film frame. Therefore something inside the camera that's shiny and is reflecting light. Have a good look with a torch. Might be a bit of shiny surface in the camera that shouldn't be there, just inside the lens mount.

Edited by Jon O'Brien
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14 hours ago, Jon O'Brien said:

Ah, so it's not actually a scratch on the film?

It's 100% a tap scratch. Reflections can't do that. 

The key is how it moves and how it flickers. Those are two indications. You may not see it on the emulsion if you aren't trained properly. You have to look at the bounced reflection from a soft white light source in order to actually see the scratch. We have one built into our scanner box and on our inspection table, it's critical for determining where scratches are. 

This is a common issue when the loop size is too big. 

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