Film information exchange system using self-clocking encoded start and stop sentinels

摘要

A magnetic layer is included as an additional layer in a photographic film. Information exchange between various uses of the film, such as the camera user, the dealer and photofinisher, is facilitated by recording data in dedicated frame-limited longitudinal track(s) in said film. All data is recorded on the film using a self-clocking three-part code in order to provide automatic data synchronization between the various users without requiring film transport at the same speed or even a uniform speed when reading and writing data. Three-part encoded binary characters uniquely representing start and stop sentinels respectively, are recorded at the beginning and end of the track respectively and facilitate automatic detection of the direction of film strip transport.