Like many of us, [Emily] found herself on COVID-19 lockdown over the summer. To make the most of her time in isolation, she put together an optical audio decoder for old 16 mm film, built using modern components and a bit of 3D printing.
It all started with a broken 16 mm projector that [Emily] got from a friend. After repairing and testing the projector with a roll of film bought at a flea market, she discovered that the film contained an audio track that her projector couldn’t play. The audio track is encoded as a translucent strip with varying width, and when a mask with a narrow slit is placed over the top it modulates the amount of light that can pass through to a light sensor connected to speakers via an amplifier.
[Emily] used a pair of razor blades mounted to a 3D printed bracket to create the mask, and a TI OPT101 light sensor together with a light source to decode the optical signal. She tried to use a photoresistor and a discrete photodiode, but neither had the required sensitivity. She built a frame with adjustable positions for an idler pulley and the optical reader unit, an electronics box on one end for the electronic components, and another pulley attached to a stepper motor to cycle a short loop of the film.
Most of the projects we see involving film these days are for creating digital copies. You can digitize your old 35 mm photo film using a Raspberry Pi, some Lego pieces, and a DSLR camera, or do the same for 8 mm film with a 3D printed rig. Continue reading “Listening To Long Forgotten Voices: An Optical Audio Decoder For 16 Mm Film”
In the sixties, videotape used to film television programs was expensive. When a program had been shown as many times as the contract required the tape was wiped and reused, unless someone requested it be saved for some reason. At least, this was the BBC’s doctrine. Many episodes of the BBC’s programs have gone missing due to this reuse of the videotapes but sometimes the films of these episodes are found in an attic or storage facility. [Cplamb] brings us the story of the salvation of some episodes of British comedians Morecambe and Wise’ first series on the BBC, their first color series.
Do make duplicates, the BBC would film a television playing one of the videotapes. This film duplicate would be sent out to television stations around the world, rather than the tapes. The Morecambe and Wise film was found in the humid basement of a television station in Nigeria. Due to the conditions, the film was “diseased” and was in danger of decomposing into soup.
A series of hacks was used to restore the episodes from the rotting film stock. X-ray microtomography was used to scan a roll of film to see if this could be used. This worked because the film has a layer of silver oxide emulsion(the image) on one side and plastic (the film stock) on the other. A program was written so that the resulting voxels could be remapped into two dimensions in order to see the original frame. However, the volume that the machine could x-ray was small – using it on an item the size of a full roll of film would probably destroy the film, if it could be done. The next hack was to cut the film into small blocks using a laser cutter. This itself seems destructive but if you can either cut it up and scan it or let it turns into soup the choice is easy.
A second part of the story has been published, but the third article in the series hasn’t been yet, so we don’t know how the resulting film looks. But this is a pretty cool story involving scanning, x-rays, programming, and laser cutters — all hallmarks of the great hacks we see on Hackaday. Check out this article on the mechanics of film projection and this one on automatically scanning 8mm film for similar style hacks.
Untold miles of film were shot by amateur filmmakers in the days before YouTube, iPhones, and even the lowly VHS camcorder. A lot of that footage remains to be discovered in attics and on the top shelves of closets, and when you find that trove of precious family memories, you’ll be glad to have this Raspberry Pi enabled frame-by-frame film digitizer at your disposal.
With a spare Super 8mm projector and a Raspberry Pi sitting around, [Joe Herman] figured he had the makings of a good way to preserve his grandfather’s old films. The secret of high-quality film transfers is a frame-by-frame capture, so [Joe] set about a thorough gutting of the projector. The original motor was scrapped in favor of one with better speed control, a magnet and reed switch were added to the driveshaft to synchronize exposures with each frame, and the optics were reversed with the Pi’s camera mounted internally and the LED light source on the outside. To deal with the high dynamic range of the source material, [Joe] wrote Python scripts to capture each frame at multiple exposures and combine the images with OpenCV. Everything is stitched together later with FFmpeg, and the results are pretty stunning if the video below is any indication.
We saw a similar frame-by-frame grabber build a few years ago, but [Joe]’s setup is nicely integrated into the old projector, and really seems to be doing the job — half a million frames of family history and counting.
Continue reading “High-Quality Film Transfers With This Raspberry Pi Frame Grabber”
When [Douglas Welcome] found a disposed Kalart Craig 16 mm Projecto-Editor on the curb, he knew it was destined for retro-greatness. This vintage looking device was once used to view and cut 16 mm film strips, and still in mint condition, it was just too cool to pass up. With help of a similarly historic Raspberry Pi 1 Model B, and a little LCD screen, [Douglas] now turned the little box into an awesome retro arcade game console
Continue reading “Vintage 16mm Film Editor Is Now Retro Arcade”