35 mm film is the
film gauge most commonly used for
motion pictures and chemical still
photography (see
135 film). The name of the gauge refers to the width of the
photographic film, which consists of strips 34.98 ±0.03 mm (1.377 ±0.001 inches) wide. The standard
negative pulldown for movies ("single-frame" format) is four
perforations per
frame along both edges, which results in 16 frames per foot of film. For still photography, the standard frame has eight perforations on each side.