Abstract: Movements of a table are optically recorded on film by mechanically gearing movement of the table to rotate a drum provided with a peripheral row of slots positioned above the film. A light is directed through the slots onto the film as the film is moved and the drum rotated thereby exposing the film to bars of light images which are skewed in accordance with the relative rate of rotation of the drum and speed of movement of the film. Playback is accomplished by developing the film and then passing light through the clear film between the new opaque exposed bars of light images on the film and slots in the drum to suitable photo-cells. During playback the film may be moved at a constant speed and the drum will remain in synchronism with the film and in view of its direct gearing to the table, the table will follow movements determined by the pattern on the film.