Simon Wyss

It could be a project to replace the magnetic heads by an optical one and feed an LED with linear signals. You’d need to install a very narrow slit between the LED and the film, maybe a microphotograph of a black line on a piece of sound recording film. The line should be clear, surrounded by opaque black, four tenths by 0.032" or so. Then you can try out photographic sound recording on the available Double-Eight stocks.

Could be that the film stripper scratches, part of the loop former assembly, most probably the upper one. Have a look at that and bend it slightly away from film towards sprocket drum, if necessary.

Yes, Mark V was an ISO 500 grey base negative film.

John, we have a misunderstanding. What I meant is edge print lettering such as the safety S and ILFORD. That would be black on clear, if genuine to the print stock.

I think it was Eastman 5302, converted by Ilford from jumbo rolls.

Found another picture

Mmh, I’m on the hook. It was named Ilford Fine Grain Safety Positive film. https://www.dia-versum.de/Ilford-Filmstrip-Printer1950th.pdf Just saw this with an ebay offer:

LASER does not etch but burn. Subtitles are in fact dotted out. In a good, sharp projection you can see a series of round points that form the letters. Depending on the adjustment of a given LASER apparatus the letter ground goes a little deeper or less. Since the yellow-dye layers are closest to the base LASER subtitles not completely through to the base, ideally into it, bear a yellow tint. Be careful with Ilford, they never made a black and white motion-picture print stock and if so, I should very much like to know when. Ilford Fine Grain Safety Positive was presumably made by a third party. Rolls no longer than 400 ft were on sale, unperforated as well. The print you have may be a color film. If it were to be Ilford black and white, the printed lettering ought to read black on clear. If you read clear on black, it’s copied from neg.

As far as mechanical and optical issues are in play I can help. Electrical and electronic parts aren’t my cup of tea. I do have soldering equipment but that’s it. Daniel Wittner still has some parts on shelves. https://www.wittnercinetec.com/epages/WittnerCinetec-Super8-16mm-Film.sf/en_GB/?ViewObjectPath=%2FShops%2FWittnerCinetec-Super8-16mm-Film%2FCategories%2F"Beaulieu R16%2F2016 Zubehör"

Negatives aren’t optically enlarged several hundred times like positives in projection. The negative image is generally transferred at one-to-one ratio on printers.

http://www.brianpritchard.com/colour_films_with_unusual_sensit.htm

The image is falling downwards meaning the film was pulled upwards in the camera or back by a too tight upper loop as I assume. Load some dummy stock and observe it run in the open camera at various loop sizes.

There are no curtains. The Filmo 70s have a rotary disc shutter that’s not easily changed. It’s not impossible but a major job. The shutter blade is caulked within the claw-shutter drive assembly. If you really have enough or even too much light, it could be worth a try to buy some Eastman 7234 from a lab that still has it. FilmoTec might sell Orwo DN 2 in 16, a minimum quantity might be mandatory there, I don’t know. Both these stocks are panchromatically sensitized and of a soft contrast. Gigabitfilm was a ISO 40 panchromatic negative stock on a colourless polyester base. I could revive this, minimum purchase is 6,000 ft, though. The new name would be Europan. You get Harman to produce Ilford Pan F plus before Rochester sits from one ass cheek onto the other.

Well made, thanks for sharing

With me, if Switzerland isn’t too far away for you