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polyester or cellulose acetate) coated with an emulsion containing light-sensitive silver halide salts (bonded by gelatin) with variable crystal sizes that determine the sensitivity or resolution of the film. When the emulsion is subjected to controlled exposure to light (or other forms of electromagnetic radiation such as X-rays), it forms a latent image. Chemical processes can then be applied to the film to create a visible image; This process is called film developing.
Depending on the type of film being exposed, the image produced is either negative polarity (must be printed to positive polarity for proper viewing) or reversal (can be viewed directly -- it is called reversal because it is developed to a negative in the first stage of processing and reversed in subsequent steps). Reversal film produces slides or transparencies, which can be viewed directly, scanned, or projected. Many professional photographers favour slide film, which often has better colour reproduction. The film is scanned before being published in magazines or brochures. Slides can be inspected for sharpness using a high-powered magnifying glass, known as a lupe, and do not need to be printed to see the actual image produced.
Film speed describes a film's sensitivity to light. Fast films are very receptive to light, slow films are not. Films are commonly given ISO (International Standards Organisation) rating on the following scale:
ISO 25, ISO 50, ISO 100, IS0 200, ISO 400, ISO 800, ISO 1600, ISO 3200
ISO 25 film is very "slow", so it requires much more exposure to produce a usable image than ISO 800 film. ISO 800, 1600 and 3200 film is thus better suited to low-light situations and action shots. The benefit of slow film is that it usually has finer grain and better colour rendition than fast film. Professional photographers usually seek these qualities, and therefore require a tripod to expose an image on slow film and keep the camera still for the duration of the shot.
Instant photography, as popularised by Polaroid, uses a special type of camera and film that automates and integrates development, without the need of further equipment or chemicals. This process is carried out immediately after exposure, as opposed to regular film, which is developed afterwards and requires additional chemicals. See instant film.
In black-and-white photographic film there is usually one layer of silver salts. When the exposed grains are developed, the silver salts are converted to metallic silver, which block light and appear as the black part of the film negative.
Color film uses at least three layers. Dyes added to the silver salts make the crystals sensitive to different colors. Typically the blue sensitive layer is on top followed by the green and red sensitive layers. During development, the silver salts are converted to metallic silver, as with black and white film. The by-products of this reaction form colored dyes. The silver is converted back to silver salts in the bleach step. It is removed from the film in the fix step.
Because photographic film was ubiquitous in the production of motion pictures, or movies, these are also known as films.
The first flexible photographic film was made by Eastman Kodak in 1885. This "film" was coated on paper. The first transparent plastic film was produced in 1889. Before this, glass photographic plates were used, which were far more expensive and cumbersome, albeit also of better quality. Early photography in the form of daguerreotypes did not use film at all.
See also: Timeline of photography technology, List of photographic equipment makers
Type: Black and White Negative
Speed: ISO 100, DIN 21
Available Formats: 35mm, 120, sheet film (9x12cm, 10.2x12.7cm, 13x18cm)
Granularity (x 1000): RMS 9.0
Latitude:
Color Saturation: n/a
Resolving Power: Contrast 1000:1 150 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Black and White Negative
Speed: ISO 400, DIN 27
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 14.0
Latitude:
Color Saturation: n/a
Resolving Power: Contrast 1000:1 110 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Negative
Speed: ISO 100, DIN 21
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 3.8
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 140 lines/mm, Contrast 1.6:1 60 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Negative
Speed: ISO 100, DIN 21
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 4.0
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 140 lines/mm, Contrast 1.6:1 50 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Negative
Speed: ISO 200, DIN 24
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 4.3
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 130 lines/mm, Contrast 1.6:1 50 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Negative
Speed: ISO 400, DIN 27
Available Formats: 35mm, 120, 220
Granularity: (x 1000): RMS 4.5
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 130 lines/mm, Contrast 1.6:1 50 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Negative
Speed: ISO 160, DIN 23
Available Formats: 35mm, 120, 220
Granularity: (x 1000): RMS 3.5
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 150 lines/mm, Contrast 1.6:1 60 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Reversal
Speed: ISO 50, DIN 18
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 10.0
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 135 lines/mm, Contrast 1.6:1 55 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Reversal
Speed: ISO 100, DIN 21
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 10.0
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 130 lines/mm, Contrast 1.6:1 50 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Color Reversal
Speed: ISO 200, DIN 24
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 12.0
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 120 lines/mm, Contrast 1.6:1 50 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Black and White Reversal
Speed: ISO 200, DIN 24
Available Formats: 35mm, 120
Granularity: (x 1000): RMS 11.0
Latitude:
Color Saturation:
Resolving Power: Contrast 1000:1 120 lines/mm, Contrast 1.6:1 50 lines/mm
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 100, DIN 21
Available Formats: 35mm, 120, Sheet Film
Granularity:
Latitude: EI 50/18 to EI 200/24
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 400, DIN 27
Available Formats: 35mm, 120
Granularity:
Latitude: EI 200/24 to EI 3200/36
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 1000/DIN 31
Available Formats: 35mm, 120
Granularity:
Latitude: EI 1600/33 to EI 6400/39, up to EI 25000/45 with push processing
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White (C41 Processing)
Speed: ISO 400/DIN 27
Available Formats: 35mm, 120
Granularity:
Latitude: EI 50/18 to EI 800/30
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White Orthochromatic Copy Film
Speed: ISO 80/DIN 20 in Daylight, ISO 40/DIN 17 in Tungsten
Available Formats: 35mm, 120
Granularity:
Latitude:
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 50/DIN 18
Available Formats: 35mm, 120
Granularity:
Latitude: EI 25/15 to EI 50/18
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 125, DIN 22
Available Formats: 35mm, 120, Sheet Film
Granularity:
Latitude: EI 50/18 to EI 200/24
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 400, DIN 27
Available Formats: 35mm, 120, Sheet Film
Granularity:
Latitude: EI 400/27 to EI 3200/36
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White with Extended Red Sensitivity
Speed: ISO 200, DIN 24
Available Formats: 35mm, 120
Granularity:
Latitude:
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 100, DIN 21
Available Formats: 35mm, 120
Granularity:
Latitude: EI 50/18 to EI 200/24
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
Type: Black and White
Speed: ISO 400, DIN 27
Available Formats: 35mm, 120
Granularity:
Latitude: EI 200/24 to EI 3200/36
Color Saturation: n/a
Resolving Power:
History:
Primary Usage:
General Characteristics:
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