The camera had an ExCLA. Working perflectly. Back from the developers, then telecined, the footage had 2 vertical lines. The film developer said:
"The camera is scratching the film".
Really, thats what he said. The camera is scratching the film. I don't think so. Here's why...
It's difficult to tell exactly where the problem is originating. Doe you have the original positive developed film? Can you see the scratches? If there are NO scratches on the positive film, the the problem is NOT with the camera. The problem does look like scratches were on on the emulsion side of the film. They could be from any of the following situations :
1) During the manufacture of the film.
2) During cutting down of the film from 35 or 16 millimeter to 8mm.
3) During re-punching of the second set of sprocket holes to
convert the film to double run.
4) During the actual running of the film in the camera to produce
5) During chemical processing of film.
6) During the telecine process.
7) During rewinding at any stage of any of the above process
Basically, we need to know WHEN the scratches occurred.
How do we know which of the above 7 processes(s) are responsible for the scratches? Only process #4 involves the camera itself. The rest are either manufacturing, developing or telecine processes.
The ExCla covers disassembly, cleaning, lubrication and readjustment. No repair work on the gate or other parts of the camera. None was noted during the ExCla. There is only 1 part of the camera that actually touches the emulsion side of the film during filming - the gate.And the Gate ONLY touches at the outer edges where it does NOT matter.
The film is wound emulsion side in from the manufacture. It is 100% protected by the backing of the next portion of wound film on the reel. 8mm file is about .008" thick made of polyester. Tough stuff.
The film first passes over the tension roller. The roller touches the film on the backing side. To do any damage the roller would have to scratch the film ALL the way through the films thickness to reach the emulsion. Not possible.
The pressure plate presses the film between the plate and the gate. The pressure plate (flips away to reload film) touches the backing side of the film. Again the pressure plate is not able to scratch the film through to the emulsion.
Finally, the film that passes through the gate and the emulsion does touch the gate, but only at the extreme edges away from the gate open area. At the point where the film does passes over the gate, it passes only over the extreme edge of the gate. There is nothing to scratch the gate anywhere. I've attached 2 images. One is the gate dimensions. The other is a picture of the Bolex 8mm gate.
The width of the gate opening (horzontally) is .177". The estimated scratch lines, are about .020" to .040" wide, relative to the gate widths. I got this by viewing a still of the footage on my HP 24" monitor and measuring the width of the scratch with a vernier caliper. The .020" to .040" estimate is about 10x to 20x the width of a human hair.
If it's anything related to problem 4 above, I will fix it at no charge. Keep in mind, this is not covered under the performed ExCLA. I do have the actual roll of expired film that I used to test your camera. I have inspected it with a 3x lens under strong light and I see no indications of the film's emulsion being scratch when I inspected it.
WHAT I CAN DO TO HELP
The are a couple of things I can do to help:
1) Send the camera to me and I will run another, different roll of test film through and look for scratches. It there are scratches added to the film's emulsion layer, after passing through the camera, I will locate and repair/replace the problem at no cost to you. If there are no scratches after running the test film, I will return the camera with you paying the return postage.
as an alternative:
2) I will send you a 1/2 roll of unexposed film and you can run it though yourself. If it comes out scratched similar to the finished film; send me the camera and the film for repair. I will pay the return shipping.
If it turns out to be a problem other than the camera adding the scratches, the problem must be with manufacturing, developing, processing or telecine.
Given the size of the scratches, relative constant position, and the relationship to the gate size, I believe the scratches were caused by 1) Developing, 2) Processing or 3) Telecine processes. As much as I hate to blame anybody, it is most likely the problem due to 1 of those 3.
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