Flatbed editor

The transports can be "locked" together, either mechanically (KEM, Steenbeck, Showchron) or electronically (Moviola), so that they move in harmony and maintain synchronization between picture and sound. They can also be unlocked to move them independently. A prism reflects the film image onto a viewing screen, while a magnetic playback head reads the magnetic audio tracks. The two most common configurations are the "six-plate" (one picture transport and two sound transports) and the "eight-plate" (two picture and two sound transport) models. (The edges of two of the plates on the six-plate model can be seen pictured at the right.) Most films are shot double-system: The picture is shot on film, while the sound is recorded separately on a quarter-inch audiotape on a Nagra III, 4.2, 4S or occasionally a Stellavox SP7. For convenience during the editing process, the sound is transferred to a magnetic track ("mag") — sprocketed recording film, which is filmstock coated with magnetic oxide, instead of photo-sensitive emulsion. One "frame" on the magnetic film equals one frame of picture.