The intermittent mechanism (or "movement") is the device by which film is regularly advanced and then held in place for a brief duration of time in a movie camera or movie projector. This is in contrast to a continuous mechanism, whereby the film is constantly in motion and the image is held steady by optical or electronic scanning methods. Intermittent mechanisms were first used in sewing machines, in order for the fabric to be fed through correctly - ensuring it is stationary as each stitch is made, while moving the required distance between stitches.

The intermittent mechanism must be employed in concert with a rotating shutter which blocks light tranmittance during the motion of the film and allows light through while the film is held in place usually by one or more registration pins. The intermittent mechanism can be accomplished in many ways, but most often, it is done with sprocket wheels, claws, or pins coupled to the camera or projector drive mechanism.

In movie theater projectors, the intermittent movement is most often produced by a Maltese Cross mechanism:

External links

• Examples of camera movements