70 mm film is a wide high-resolution film gauge for motion picture photography, with a negative area nearly 3.5 times as large as the standard 35 mm motion picture film format. As used in cameras, the film is 65 mm (2.6 in) wide. For projection, the original 65 mm film is printed on 70 mm (2.8 in) film. The additional 5 mm contains the four magnetic stripes, holding six tracks of stereophonic sound. Although later 70 mm prints use digital sound encoding, the vast majority of existing and surviving 70 mm prints pre-date this technology.
A 70 mm film strip with a human hand for scale
Faded vintage 70 mm positive film with four magnetic strips containing six-channel stereophonic sound
35 mm film is a film gauge used in filmmaking, and the film standard. In motion pictures that record on film, 35 mm is the most commonly used gauge. The name of the gauge is not a direct measurement, and refers to the nominal width of the 35 mm format photographic film, which consists of strips 1.377 ± 0.001 inches (34.976 ± 0.025 mm) wide. The standard image exposure length on 35 mm for movies is four perforations per frame along both edges, which results in 16 frames per foot of film.
35 mm movie film
A photo of a 35 mm film print featuring all four audio formats (or "quad track") — from left to right: SDDS, a soundtrack as an image of a digital signal (blue area to the left of the sprocket holes); Dolby Digital sound (grey area between the sprocket holes labelled with the Dolby "Double-D" logo in the middle); analog optical sound, optically recorded as waveforms containing the audio signals for the left and right audio channels (the two white lines to the right of the sprocket holes); and the
An "over-under" 3D frame. Both left and right eye images are contained within the normal height of a single 2D frame.