70 mm film

70mm film (or 65mm film) is a high-resolution motion picture film format. As used in camera, the film is 65mm wide; for projection 2.5mm are added along each side for magnetic strips holding six tracks of surround sound. Each frame is 6 perforations tall, with an aspect ratio of 2.20.

65mm/70mm became popular during the 1970s and 1980s for the wide screen, sharp picture and, most importantly, high quality sound. The advent of low-grain film stocks and availability of digital soundtrack systems for less expensive and more widely projectable 35mm film have lead to a decline in use of this expensive format in recent years.

A horizontal variant of 65mm/70mm, with an even bigger picture area, is used for the high-performance IMAX format.