Program a machine that applies acid to precision-etch metal and plastic.
Tends film or magnetic tape dubbing machines that play back recordings of music, dialogue, or sound effects to facilitate synchronization of sound motion-picture film action by RERECORDING MIXER: Loads reels of film or tape onto machine and passes lead-end over and around sprockets, wheels, tension rollers, and magnetic tape head or over photo-electric cell apertures. Starts machines, unwinds film or tape, and stops machine when mark on tape or film indicates beginning of sound. Switches machine to automatic for control by RERECORDING MIXER. Informs RERECORDING MIXER that machines are loaded and ready for playback. Removes reels when recordings are finished and rewinds tape or film onto original reel.