Scratching film ...

[TomR55]

I have a well-used Leica M4-P that has just recently scratched an entire roll of film. I checked the pressure plate and it appears clean. I note that the scratches are consistent, appear on nearly every frame, and are on the "shiny side" (non-emulsion side) of the film. This particular camera had occasionally scratched film but as of this week it appears that the problem is getting worse.

A few years ago I had a similar problem (albeit less pronounced) and a repair person fixed it by polishing the plate. Is this something that I can do with some help from knowledgable people or is this something best done by someone who CLAs these cameras?

 

[mshchem]

Youxin Ye will repair at a responsible price. I would look for dirt etc. You could wipe off the plate with a damp rag or a chamois. Worth a try.

 

[Don_ih]

I would advise running a different roll through before anything. The scratches may have been from the light-trap material in the film cassette.

 

[snusmumriken]

I would advise running a different roll through before anything. The scratches may have been from the light-trap material in the film cassette.

Yes, exactly; and if not too late, check whether the scratch continues along the cut-off ends of the film. That might require some thought if you home-load cassettes from bulk, but you should be able to figure out which bits have been past the light trap in the loader, the light trap in the cassette, and the pressure plate in the camera.

Does anyone here know what the finishing process is on Leica pressure plates? Are they polished and then blued, or blued and then polished?

 

[TomR55]

I would advise running a different roll through before anything. The scratches may have been from the light-trap material in the film cassette.

My thoughts, exactly. I'm planning on putting a roll of Kentmere through that same camera within the next day or so. I think that I've seen intermittent scratching with Kodak cassettes (and this was TMax film, but to be sure ... .

Oh, and these scratches run almost the entire length of the film ... including the blank exposures prior to the first ... .

Thank you for the recommendation; I'll keep the post apprised.

 

[snusmumriken]

Oh, and these scratches run almost the entire length of the film ... including the blank exposures prior to the first ... .

Including the bit that didn’t leave the cassette?

 

[TomR55]

I just retrieved the trimmed leader (or so I think .... a few other leaders appeared in that rubbish bin...) and it has NO evidence of scratching. I will definitely run another roll early next week and process it with my regulars. I shall certainly retain all bits from the leader to the trailer to ensure its status.

Thanks for the directed question!