35 mm film

35 mm film is the basic film gauge most commonly used for both still photography and motion pictures, and remains relatively unchanged since its introduction in 1892 by William Dickson and Thomas Edison, using film stock supplied by George Eastman. The photographic film is cut into strips 35 millimeters (about 1 3/8 inches) wide — hence the name. The standard negative pulldown for movies ("single-frame" format) is four perforations per frame along both edges, which makes for exactly 16 frames per foot (for stills, the standard frame is eight perforations). A wide variety of largely proprietary gauges were used by the numerous camera and projection systems invented independently in the late 19th century and early 20th century, ranging from 13 mm to 75 mm (0.51–2.95 in). 35 mm was eventually recognized as the international standard gauge in 1909, and has remained by far the dominant film gauge for image origination and projection despite threats from smaller and larger gauges, and... full article at wikipedia