IMPLICIT MID ROLL INTERRUPT PROTECTION CODE FOR CAMERA USING DEDICATED MAGNETIC TRACKS ON FILM

A virtually transparent magnetic layer is included as an additional layer in a color negative film. Information exchange between various users of the film-such as (for example) the film manufacturer, the camera user, the dealer and photofinisher-is carried via plural longitudinal magnetic tracks on the film that begin and end in individual frames. Each track is dedicated to the writing and reading of a predetermined set of parameters related to the corresponding frame. All data is recorded as N-bit character where N is preferably six. Each track is preceded by certain six-bit character called an ID sentinel. On-film magnetic data recording by the film manufacturer uses an ID sentinel different from that employed in the camera. The camera automatically prevents exposure of any frame bearing a camera ID sentinel, thus providing protection from double exposures.