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I am designing an electro-optical musical instrument that will use sound waves printed on 35mm film. It would require long strips of film over 1 meter long.

I would like to generate the waves on a computer and then digitally print them on film. It would also be a requirement that there are no frame dividers, so a continuous uninterrupted pattern.

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    on the frame dividers - there are already no frame dividers on 35mm film. Frame dividers only appear because of the camera exposing one area, winding on, exposing the next, and so on – osullic Apr 8 '17 at 10:30
  • Is transparency required, i.e. are you reading it by shining light through it, or reflected off of it? I ask because one option may be to print on vinyl (like the stretch-fit they put on cars, buildings, etc.) and then transfer to the film stock? – Linwood Apr 8 '17 at 14:12
  • @Linwood Yes transparency is important. I did use vinyl on a smaller disk version. This time I want to use variable transparency represent the waveforms. – John Spence Apr 8 '17 at 15:50
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    While not 35mm film, why not switch to 8mm film and simply point a cheap 8 mm camera at some sort of projection screen. – Peter M Apr 8 '17 at 19:19
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    If you're just doing audio, is there anything wrong with having a soundtrack printed onto the edge of 16 or 35 mm film and using the guts of a projector to read it? – Blrfl Apr 9 '17 at 16:34
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In the past, film recorders were commercially available for transferring digital images directly to photographic media. Typically, they produced 35mm slides rather than continuous output. Used examples currently are available at low cost on Ebay but the commercial market is probably long since gone because the trends are in the opposite direction (photographic film -> digital).

I suspect that the most practical method for your application is to build your own equipment or to utilize something like a strip chart recorder instead of photographic film.

enter image description here

  • Would those handle 12, 20, 40 megapixel images? Could be interesting for projecting images. – gerrit Nov 15 '17 at 22:37
  • Certainly not every model - some of these devices will be from the days where 1280x1024 was considered extreme high resolution. – rackandboneman Nov 2 '18 at 16:19
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I am a graphic designer, so probably you could use another point of view.

Introduction

When you are printing on offset you can prepare the design directly on a metal plate (direct to plate) or you can a high contrast film before preparing the plates.

Pre press High contrast film

https://www.google.com/search?q=negatives+film+pre+press

Obviously, the machines are really expensive, but you can find a provider near you and the exposed and developed film is really cheap (I calculate that a 70x95cm is around $10 USD)

There are smaller sizes of roll film, and probably you can find a provider that can expose for example a 30cm strip by one m or more of film.


Preparing the design

Then you need to prepare your soundwave in the correct resolution. You can go as high as 4800 ppi in 1 bit images, but probably 1200ppi will be fine.

Use 1 bit images, if you use a normal grayscale image you can only use 300ppi and the result will be screened.

Then you can cut the strips using a normal cutter, and you can try to find a way to make the perforations.

This is the approach I would use.

If you want more detail, ask in the comments.


2001 space odyssey

Another method could be using a slit scan technique

https://www.google.com/search?q=Slit+scan+2001+space+odyssey

which consist in exposing the film thru a slit.

You can probably construct a rig to slide the film behind the slit, and expose it using a normally led monitor shooting an animation...

There were rolls of 35mm film of 100 foot long strips, like Kodalith ortho 6556.

https://www.google.com/search?q=kodalith+ortho+6556

But I still would use the normal prepress film, which gives you an exact resolution and dimensions (therefore timing).

The disadvantage I think is the low resolution you will achieve, but if you want to invest money you could use a lens to shoot a very focused beam...


For the perforations

There is something called die cutting. You could have some troubles aligning the cut to the exposed film, but there are ways to work that.

https://www.google.com/search?q=die+cutting

The advantage of using a prepress film + die cutting is that you can prepare several meters of music and print them and cutting them in one step.


Do it on a backlight synthetic paper

There is a very specific type of material for backlight posters, that are printed on inkjet-based systems, the problem is that the plastic is not transparent, but translucent. But take a look. The cutting would need to be done the same way of the prepress negative.

https://www.google.com/search?q=backlight


Offtopic

Define your system.

Check some of ways sound has ben used in film history:

https://www.google.com.mx/search?q=sound+on+film

It has being using variable density, where you need bit depth, or variable area, where you can use lith film (high contrast)

enter image description here

If you can use the variable area aproach, you can use the prepress method. If you need variable density you could construct something like this:

enter image description here

This can also could make variable area.

The problem is that any change in the rolling speed, will give you unacurate results.

I would stick to the digital print.

  • Thank you, there are some more options there that I had not thought about. So the printer you described there is a trade off between bit depth and resolution, because it is using dithering to simulate grey scale? – John Spence Apr 9 '17 at 22:21
  • Yes, exactly. When printing you use a high contrast film, so you can not have a grayscale. To simulate grays you can either dither or screen it. Take a look at this post: graphicdesign.stackexchange.com/questions/64298/… An inkjet printer also do not shoot different levels of gray, it shoots the same black ink dithering it. – Rafael Apr 9 '17 at 22:59
  • So is there no such thing as a printer that can print the dots as grey scale, so you could have higher resolution or bit depth? This would be possible with a laser film printer because it could change the brightness of the laser. Maybe such a printer would be used for printing slides or something that is intended to be enlarged. – John Spence Apr 10 '17 at 7:34
  • 1) For prepress there are not grayscale films, all are high contrast. 2) Neither a laser printer nor an inkjet printer print gray, they either put a dot or not. 3) There could be canisters of panchromathic 35 mm films, but I doubt you can use a laser to expose it. It would be easier to make an optical printer. – Rafael Apr 10 '17 at 19:12
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Many years ago I used a normal inkjet printer with OHP transparent film cut up and inserted into slide mounts. The quality was a bit poor but printers have improved a lot (since the 90s). That would be fine if you only wanted up to the length of A4 or equivalent (around 30cm). Manually cutting and splicing wouldn't be impossible but wouldn't be a scalable solution either.

Continuous inkjet printing is also possible. If you can find transparencies in continuous form (or clear vinyl - I know it exists from buying some white vinyl recently) you may be able to get something that works. I suggest cutting after printing as most printers are designed for more than about 10cm paper width. Your comments hint at a need for sprocket holes. Making a suitable punch would be difficult.

  • I tried printing similar patterns on an inkjet printer many years ago. The results were not good, but I think the printers are a lot better now. I will still try to find a company with digital film printer because I think they will have the best results, but probably a lot more expensive than inkjet. – John Spence Apr 9 '17 at 8:32
  • A sprocket hole cutting machine is probably very rare. There are companies that make custom punches for all sorts of applications, not something I know much about. Maybe a laser cutter is an option. – John Spence Apr 9 '17 at 8:39
  • A laser cutter should be able to do it. I assume you need the standard sprocket pattern, because if not there are simple alternatives. – Chris H Apr 9 '17 at 9:29

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