The art of sound pictures (1930)

SOUND TECHNIQUE 225 have been translated into light rays and photographed on the edge of the film, other light rays have traveled directly from the face of the actor through the lens of the camera and have left their pictorial record on the same strip of film. If the photographs of the sound and the photographs of the actor are recorded at precisely the same time on the same strip of film, then the two are said to be S5mchronized. In other words, s5mchronization means simultaneous timing of sound record and pictorial record upon the film. If the sound recording apparatus is built into the camera, then the sound and picture records are automatically and perfectly synchronized. But other methods of s5mchronization are required when sound and picture records are made separately. On the sound stages in big studios, the picture record is usually taken on one film, and the sound record on another. The film upon which sound is recorded is run in a sp>ecial room completely shut off from the rest of the sound stage. Yet, the film upon which the sound record is made must be run at precisely the same speed as the film in the camera upon which the pictures are recorded. Marks are then made on the two strips of film, so that the records can be matched and subsequently printed upon the same film. Synchronization, according to this system of recording, is done by means of electric motors winding both strips of film, and so connected and regulated that they can be started and stopped simultaneously and run at precisely the same rate of speed. In studio parlance, these two motors, thus connected, are said to be interlocked. When several actors are performing on the same set, a number of microphones are generally required to catch