Instant film

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Instant film is a photographic film that is designed to be used in an instant camera (and, with accessory hardware, with many professional film cameras). The film pack contains the chemicals needed for developing, and the instant camera automatically initiates the developing process after a photograph has been taken. In most types of Polaroid instant cameras, the film is pulled out through rollers which break open a pod containing the chemicals. The chemicals spread out over the surface of the film, and the positive image appears a few seconds to minutes later. The chemicals have time delays built into them so that each layer of the film can be processed in the correct order. Instant film is available in sizes from 24 mm x 36 mm (similar to 135 film) up to 8" x 10" size, with the most popular film sizes for consumer snapshots being approximately 3¼" x 4¼" (the image itself is smaller as there is a border surrounding the image). Early instant film was distributed on rolls, but currently is typically distributed folded into film packs of 8-10 exposures that allow each image to be removed from the camera after it has exposed. Some modern film packs also contain a flat electrical battery to drive motors in the camera. This inclusion of the battery with the film ensures that a properly charged battery is always available for use. Single sheet films are also available for use in large format cameras.

Instant film is frequently used in situations where it is necessary to validate soon after taking a photograph that the resulting image was suitable, such as in documenting evidence in law enforcement, in health care and scientific applications, and producing photographs for personal identification, such as for use in passports. Instant film is also used by artists to achieve effects that would be more difficult to accomplish with traditional photography, by manipulating the emulsion during the developing process, or separating the image emulsion from the film base. Instant film is being rapidly supplanted by digital photography and printing (using home dye sublimation, inkjet, and laser printers.)

Instant film is notable for having had a wider range of film speeds available than other negative films of the same era: instant film has been produced with ASA 4 to ASA 20,000. Current instant film formats typically have an ASA between 150 and 3000.

Besides Polaroid, Fuji also produces instant film. Kodak was prohibited in 1986 from further selling instant cameras and instant film. However the initial film for Polaroid was manufactured by Kodak. The patent infringement came about when Kodak tried to avoid the patent by placing the emulsion layers in the reverse order. The courts ruled that this was in fact an infringement on the patents held by Edwin H. Land and the Polaroid company.

An instant motion picture film, Polavision, was introduced by Polaroid in 1978, with an image format similar to Super 8 mm film, and based on an additive color process. Polavision required a specific camera and tabletop viewer, and was not a commercial success, but did lead to the development of an instant 35 mm color slide film.

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