Yet again, scratched negatives, no cause found

[Vonder]

I have yet another body that scratches negatives. It's a Minolta XE-7 and it's pretty bad. The thing is, the scratches are (and in every other camera I've seen this in) on the non-emulsion side, like, they're coming from the film pressure plate. But THAT item seems to have a perfectly smooth surface. Anyone ever have this issue and track it down? I would love to fix this body if I can but it'll go in the trash if I can't fix it.

Example image:

 

[Pioneer]

Wolfeye, is this factory film or are you reloading. If reloading the scratches could be coming from the reloader or from the cassettes you are using.

 

[Vonder]

This is factory film.

 

[Mr Bill]

Wolfeye, try stopping the film partway through the camera. Make a reference mark, then remove the film. If you see a point where the scratch suddenly stops, this should show the exact position in the camera where it comes from. Good luck.

 

[summicron1]

where are you getting the film processed? Some commercial processors, especially cheap ones, are not all that good at keeping their equipment clean. Just before the local costco quit doing film i noticed my film from them coming back pretty scratched up.

Try some black and white and soup it yourself, or just run a roll through the camera, rewind it, take it out, open the can and inspect the film. This way you eliminate the camera, or confirm it.

 

[Xmas]

It can be the pressure plate.

There need not be any visible mars so either use a jewlers loope (a camera lens makes a good substitute) or rub film on the plate by hand orthogonal to normal movement and compare scratches with exposed film.

Treating a rust eruption difficult brass or silver metal polish first option on cotton bud (q tip) for America (cousins).

 

[Fast14riot]

I had this exact issue a while back. It was in my Yashica Electro 35 GSN and Kodak Gold 200. I take my film to a professional lab and they were stumped as well. I gave them the camera and told them to hang onto thenegs to find out the issue, they tracked it down to poor handeling during development. Camera was ruled out because the scratches weren't all in the same place or direction like the pressure plate would cause.


-Xander

 

[elekm]

That's probably debris on the negative.

A scratch probably would be a darker color.

Look at the negative and see if you can wipe off the "scratch" with a moistened tissue or cotton ball.

If not, then maybe it is a scratch.

 

[Vonder]

An update - I'm pretty sure it's the pressure plate, although it feels smooth to me. I repainted it but that did no good. So I now have it removed and will sand it and repaint it once again. I'm not sure what sort of paint to use though. My black acrylic seems to hold up pretty good.

 

[Xmas]

well if you have repainted it you need the paint to be cured completely then you need to polish it with fine abrasive like metal polish on a plate glass

you need an optical flat, Leitz used a glass plate in early M3s

 

[gone]

If you've been having a run of cameras that scratch the negs, I'd look to other possibilities. Change labs, change film type, and make sure your camera is spotless inside. I've had cameras w/ less than pristine pressure plates that didn't scratch the negatives. In my experience, it usually comes from the lab, dirt in the camera (it doesn't take much, so tap it on the counter several times and blow it out each time) or a bad batch of film. The ringer here is that you stated that you repainted the pressure plate. So that's a potential source of issues if you haven't polished it smooth w/ a rag or something.

 

[Xmas]

I have two exackta IIa one scratches one does not if I swap plates the problem moves...

 

[Jojje]

I've never noticed scratches on my self-developed films but some times the colour films developed in labs have them...

 

[elekm]

I would shoot a roll of black and white film and process at home to see if it's the lab or the camera. Either that, or try a different lab or a different brand or batch of film.

The idea is to eliminate possibilities: the film, the film cassette, the lab, the camera, etc.

 

[Vonder]

An update, some definite success.

Removed, sanded, and repainted the pressure plate. I tell you in all honesty, the world is full of dust. It's everywhere, but most of it seems to be centered in my garage. So, *sigh* the paint dried with some dust in it. It still felt pretty smooth, so I popped it back in and did some tests. Looks good! I am now debating whether to leave well enough alone, or try and remove the paint once more and try for a cleaner application...

 

[ME Super]

If it's no longer scratching your film, I'd leave it alone.

 

[DWThomas]

If the new paint is sound, one could consider a light buffing with rubbing compound or very fine Scotchbright or some similar mild abrasive to remove dust blivets and leave a smooth satin surface.

 

[Xmas]

If it's no longer scratching your film, I'd leave it alone.

sage advice

 

[Mr Bill]

Something to keep in mind is that films are not all equally sensitive to scratching. Improving scratch resistance has long been a design goal with professional color neg films (I'd guess this is also true with B&W films, but have no basis to be sure).

My point is, being scratch-free on one film doesn't necessarily hold for all films. So if you find that scratches periodically show up, pay attention to the type of film being use.

 

[railwayman3]

Something to keep in mind is that films are not all equally sensitive to scratching. Improving scratch resistance has long been a design goal with professional color neg films (I'd guess this is also true with B&W films, but have no basis to be sure).

My point is, being scratch-free on one film doesn't necessarily hold for all films. So if you find that scratches periodically show up, pay attention to the type of film being use.

You're correct - I was given an old Exa camera a few years ago, fine with Kodachrome and most B&W, but scratched very badly on other E6. Yet the pressure plate seemed clean and free of anything abrasive, never solved what was wrong.