Film Stock

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Film Stock

BASE AND EMULSION
GAUGE AND SPEED
BLACK-AND-WHITE AND COLOR
FURTHER READING

In 1889, Eastman Kodak introduced a flexible, transparent roll film made from a plastic substance called celluloid. Kodak chemists had perfected the celluloid film that had been invented and patented in 1887 by the Reverend Hannibal Goodwin. In 1891, working under Thomas Edison (1847–1931), W. K. L. Dickson (1860–1935) designed the first motion picture camera, the Kinetograph, which used Kodak celluloid film stock. By 1911, Kodak was manufacturing over 80 million feet of film stock annually for the film industry, and the company continued to be the major supplier of film stock internationally throughout the twentieth century. With the rise of the digital age in the twenty-first century, Kodak has evolved to produce and support digital filmmaking and projection equipment.

BASE AND EMULSION

Celluloid film is made up of a flexible, transparent base that is coated with a gelatin layer (the emulsion), which contains millions of tiny, light-sensitive grains. When the film is exposed by the shutter in the lens, the grains absorb light, creating a latent image that is not visible to the naked eye. The film is then treated with developing chemicals, which cause the exposed portions of the film to become visible in a negative image of the original scene: light and dark areas in a scene are reversed. The film is then "fixed," which removes the developing chemicals, and the undeveloped grains are washed away to prevent further exposure of the film. The negative film is then printed by allowing light to pass through it onto a second strip of film, creating a positive film for projection.

Early film stock was made of cellulose nitrate, an extremely flammable plastic. Nitrate film burns rapidly, even without a supply of air, and gives off poisonous and explosive gases. It has even been known to ignite spontaneously. Cameramen had to be extremely careful when using and storing nitrate film; one spark from a cigarette could cause an entire day's work to go up in flames. In 1897, a fire broke out in a French movie theater that was projecting a nitrate-based film, killing over 180 people. In 1914, a fire began in a California film-finishing house, destroying ten buildings. Kodak introduced a flame-resistant, cellulose triacetate film stock, also known as Safety Acetate, in 1909. But the film industry resisted Safety Acetate, which was less flexible, harder to splice, and wore out more quickly than nitrate film; studios continued to use the more flammable celluloid until Kodak introduced Improved Safety Base Motion Picture Film in 1948.

A few early film cameras used paper film stock. Evidence suggests that around 1883, French photography enthusiast Louis Le Prince (1842–1890) built and experimented with a single-lens camera that used a paper negative film. Prior to 1912, the Kinora Film Company offered an amateur camera and viewing device that utilized paper film stock in a flip-book format.

GAUGE AND SPEED

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 stressed 8 mm's "family record" function. The famous Zapruder film, which recorded the assassination of John F. Kennedy in 1963, was shot using 8 mm film. In 1935, Kodachrome color film stock was introduced in both 8 mm and 16 mm gauges; by the 1950s, color amateur filmmaking had become very popular.

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.

BLACK-AND-WHITE AND COLOR

Until 1925, Hollywood studios used orthochromatic Eastman Standard Negative stock. Orthochromatic film was only sensitive to the brightest natural light, so large ultraviolet lamps had to be used during shooting. It also registered only blue light, so anything colored red showed up on the film as black. This posed a problem for actors and actresses, whose flesh-toned faces appeared darker than normal on screen. Thus began the practice of using heavy white pancake makeup on the majority of screen personalities. In 1922, Robert Flaherty shot his documentary Nanook of the North on orthochromatic film stock, which beautifully accentuated the harsh, colorless landscape.

In 1922, panchromatic film, which was sensitive to all colors, became available for black-and-white filmmaking. The hard-edged blue orthochromatic gave way to the softer gradations of "pan," providing much more natural-looking visuals. But the film industry was hesitant to switch formats, believing orthochromatic was "good enough" to suit its purposes. In 1926, Flaherty shot Moana, a documentary containing lush, tropical scenery, using panchromatic film. It convinced Hollywood to make the change, and by 1930, orthochromatic film manufacturing had been discontinued.

Color was achieved in early cinema through methods of postproduction tinting and toning. Tinting is a technique that applies one or more colors to certain areas of the film stock by hand. The practice began as early as 1895, in an Edison-produced film, Serpentine Dances. In the film, a woman dances in circles as her dress and scarves change colors, as if by magic. Edison's crude tinting techniques proved difficult on the eyes, but by 1905, a stenciling process was perfected that created a bit more accuracy in color distribution on the celluloid. Georges Méliès (1861–1938) used tinting in Le Rêve d'un astrome (An Astronomer's Dream, 1898) and the first version of Le Voyage dans la lune (A Trip to the Moon, 1902); The Great Train Robbery (1903) contained tinted sequences, including the gunshot blast directed at the audience in the last scene.

Toning imparts a color to an entire black-and-white film. By 1920, over 80 percent of all Hollywood feature films used toning to represent particular settings or emotions: for example, amber for day or interior shots, blue for nighttime, red for battle scenes. In 1921, Kodak began manufacturing pre-toned film stock in nine different colors. After the arrival of sound technology in 1927, tinting and toning were temporarily halted because the processes interfered with the soundtrack, which ran alongside the image on the celluloid. By 1929, this problem had been corrected, and Hollywood continued to use tinted and toned stock copiously until more sophisticated color filming techniques were perfected—the preview trailer for The Bride of Frankenstein (1935), for example, was shot on green-toned film stock.

Dozens of experimental processes were tried in the early 1900s to capture realistic color on film, but most lacked quality and were quickly abandoned. Technicolor was invented in 1917 by Herbert Thomas Kalmus (1881–1963) and Daniel F. Comstock and eventually became the industry standard in Hollywood. The first version of Technicolor superimposed two colored images (one green, one red) onto the screen simultaneously. The process was too expensive to use for an entire feature film, but Technicolor sequences in black-and-white films quickly became fashionable in Hollywood—for example, in Cecil B. DeMille's The Ten Commandments (1923).

In 1932, Kodak introduced a Technicolor film stock capable of reproducing a reasonable range of hues, using a three-color process. With three strips of black-and-white film running together through the camera, the color image was recorded by separating its green, blue, and red properties onto each of the corresponding color-sensitive negatives. From these three negatives, three more strips of film (known as matrices) were printed; these were used to transfer corresponding dye images onto a single blank piece of film. Walt Disney was one of the first filmmakers to experiment with this process, creating Flowers and Trees (1932), the first animated short in full color.

During World War II, German manufacturers produced the first single-strip color negative, which is still in use. This process used three sensitive photographic emulsion layers, or tripacks, coated on a single base support. The eye perceives different wavelengths of light as particular colors in the spectrum. Special chemicals sensitive only to a specific group of light wave lengths allow for an image of a different color to be processed on each layer of film (blue, green, and red). This composite image is processed, much like black-and-white film, in negative, so colors are reversed until printed in positive. By 1953 this process was well established in the film industry; by 1955, the three-strip process had disappeared from use completely.