A specialized, big-screen film format about ten times larger than the traditional cinema format (35mm) and three times larger than the standard 70 mm widescreen format; IMAX films are shot and projected on 15 perforation/70mm gauge film - "15/70", the largest film format in existence, which produces incredible high-definition sharpness in films projected on up to eight-story high screens (often dome-shaped) in theatres equipped with advanced digital surround-sound systems.