At Gamma Ray Digital, we’re building a 70mm scanner. Actually, it’ll do more than 70mm, since it’s based in part on things we’ve learned from our Lasergraphics scanner and from rebuilding an old Imagica scanner several years ago.
I’ve set up a flickr album here where I’m putting the photos as we go.
The scanner started as a Cintel Ursa Diamond telecine. We picked up the chassis for free after the parts were removed by someone who bought it and didn’t want to deal with the heavy stuff. In order to make this work as a 70mm scanner, the whole transport was simplified, the mirror housings enlarged, and all the remaining electronics were stripped from it. The chassis is nice in that the lower section and the bridge above it are all standard 19" equipment racks, so we have a place to put the host computer, shelves, and all the motion control hardware.
The goal is to make a scanner capable of scanning 35mm 4-8perf and 70mm 5-15perf. We’re building it specifically to handle weird formats that most scanners can’t - things like 10perf 70mm, a largely scientific format.
The current camera is a Vieworks VN-16MC, which is a pixelshift CCD imager that can produce a 14.5k image. We will likely swap this out for something running a Sony IMX 411, which is about 14k as well, but is a more modern sensor with excellent S/N and better low light capabilities.
Motion control is being done with off the shelf PLCs from Velocio. LED lighting is all custom, with two banks of separate RGB LED COBs. Each bank is tuned differently - one for neg and one for print. These are controlled by custom built drivers.
The transport is very simple: all PTR rollers including the drive capstan. Tension is held using AC torque motors, just as the Imagica scanners used. This is a very simple way to maintain tension on the film, and can be fine-tuned fairly easily with the use of external torque motor controllers (we’re using Oriental Motor controllers and motors).
Drive is handled with a closed-loop stepper motor that has a built-in encoder so you can accurately track position. We’ll be doing frame registration in OpenCV using the perfs as references, and the scanner is intermittent motion. It will not be fast. With the current camera, 1FPS is probably the best we can expect. if we upgrade to the Sony sensor, maybe 3-5fps.
In terms of capabilities, it will do sequential R-G-B scans, and will also do 2 and 3 flash HDR scanning.
The capture software is also custom built, written in the Xojo programming language. We’re starting on this part now.
Feel free to ask any questions you might have. I’ll be adding to that album over the coming weeks as the freshly powder-coated pieces get installed, the motors are installed and hooked up, and we start assembling the lamp house.
Oh, and about the name: The Imagica 70mm scanner at Fotokem has long been nicknamed Bigfoot. Since we borrowed so much from that design, and it’s one of the only other high resolution 70mm scanners out there, it only seemed fitting to call ours Sasquatch.