I had the honour to meet Laurent Mannoni in his warehouse full of ancient film projectors and camera’s at La Cinémathèque française. I wanted to learn how the first film projectors worked. To find what way would be best to eventually build a DIY 16mm LED projector, which would be easy enough to reproduce for others.
One of the complexities of a projector is how to make a frame on the film stand still for a moment, and later be transported to show the next frame in still position, and so on. This 24 times per second. I learned that, in the early days of film, there where mainly three ways to make the frame stand still for that short moment.
The Maltese Cross is the technique that is still used in common 16mm projectors. It’s the most robust way of moving the frame, but also the most complicated to build. In this video you can see the maltese cross in a 16mm hand crank projector. Normally the cross is inside a box with oil so it doesn’t wear out.
The Bouly Movement was used on some 35mm projectors. A thick soft material is attached on a wheel that only transports the fed through film. Thus by pressure. It was not used for long, even though at the same time it should still work quite well. On 16mm film though the part’s might get to small to make it work.
At last there was the Dog Movement. A little bend pol would push the film one frame further, as shown in this video.
The shutter is a plate, or a mask, that blocks the lens of the projector from light coming through at the moment the film is actually transported. Like the big aluminum plate in the above video. This photo shows why these days this masking plate is build in the projector itself. Imagine the metal platter spinning 24 times per second..