Film stock is available in a number of gauges, or widths. Wider gauges project a sharper image, while smaller gauges tend to be grainier. A number of experimental widths have been used in filmmaking throughout the history of cinema, but the most common gauges still in use today are 35 mm, 16 mm, 8 mm, Super 8 mm, and 70 mm.
Thirty-five mm, the gauge used in Edison's Kinetograph, quickly became the common width for filmmakers around the world. The Lumiére Brothers (Auguste [1862–1954] and Louis [1864–1948]) also used 35 mm film in their Cinématographe camera. In 1929, the American Academy of Motion Picture Arts and Sciences declared 35 mm the standard gauge of the film industry, and it remains the standard commercial gauge.
Because of its flammability and expensive two-step developing process, 35 mm was not a viable option for amateur filmmaking. In 1914, Kodak began experimenting with 16 mm acetate film that ran through the camera twice via a reversal method that produced a positive image film that did not need to be printed from a negative. The film was designed as 16 mm so that 35 mm nitrate film could not be split in half and slipped into the camera. Kodak didn't release the new gauge until after World War I, in July 1923. In 1928, Eastman Teaching Films, a subsidiary of Kodak, produced 16 mm films for use in the classroom on a range of academic subjects. In the late 1920s, studios began reprinting 35 mm commercial films on 16 mm and selling them for home viewing. But 16 mm didn't become commercially popular until World War II, when it was used for army training, education, and entertainment. Medical and industrial companies also began to use it for research purposes.
Since the 1920s, experimental, avant-garde, and independent filmmakers have used 16 mm for artistic or professional purposes. Some notable 16 mm films in this category include Chelovek s kino-apparatom ( The Man with a Movie Camera , 1929) by Dziga Vertov, Meshes of the Afternoon (1943) by Maya Deren, Wavelength (1967) by Michael Snow, and El Mariachi (1992) by Robert Rodriguez.
In 1932, Kodak introduced 8 mm, a gauge that used the same processing equipment as 16 mm but cost about one third as much. Eight-mm cameras used 16 mm film that ran through the camera twice, each time exposing only half the film. The film was then slit in half and the two pieces spliced together. Eight mm (sometimes called "double eight") appealed greatly to the home movie market. The gauge was intended for moderate-income families, and Kodak devised marketing strategies that
The next significant advance in amateur film stock came in 1965, with the release of Super 8 mm. The new gauge came pre-split and loaded in a drop-in cartridge, which eliminated 8 mm's tedious threading process. Super 8 mm could also project 50 percent more image area than regular 8 mm, because of a reduction in the size of the sprocket holes. By the end of the 1960s, most film stock manufacturers had halted production of regular 8 mm production altogether. Jim Jarmusch used Super 8 mm to film The Year of the Horse (1997), documenting Neil Young and Crazy Horse's concert tour.
Seventy-mm film, which projects an extremely high-resolution picture, became popular for commercial use in the mid 1950–1960s. When used in the camera, this film stock is actually 65 mm wide, but the negative is printed onto 70 mm film to allow for six tracks of surround sound. Seventy-mm's wide-screen format, sharp picture, and high-quality sound made it an ideal format for epics like Ben-Hur (1959), Cleopatra (1963), and Lawrence of Arabia (1962). The advent of low-grain 35 mm film stock and digital soundtrack systems led to a decline in 70 mm use in the 1990s, and few 70 mm films are made today. A horizontal variant of 70 mm is now used for IMAX films.
The speed (sensitivity) of the film stock also affects the quality of the image in projection. Slow film stock is less sensitive to reflected light, so brighter light sources are necessary during shooting to produce sharp images. Slower stock also creates less contrast between light and dark areas within a composition; fast film stock is very sensitive to reflected light and produces distinct contrasts between light and dark within the frame. Fast stock is often used for documentaries, in settings where light options are limited, and in fiction films that try to capture a stark, documentary feel. Film noir , a genre popular in the 1940s, took advantage of faster film stock technology to capture striking shadows and slick, rainy, nighttime streets. Film stock is assigned a numeric value according to speed standards established by the ASA (American Standards Association), which became the basis for the ISO (International Organization for Standardization) speed system, now currently used worldwide. Doubling the value doubles the film speed, so a film stock rated 800 is twice as fast as one rated 400.