Instant film comes in 24 mm × 36 mm (comparable to 135 film) all the way up to 50.8 cm × 61 cm size, while the most popular film sizes for consumer snapshots are approximately 83mm × 108mm (the image itself is somewhat smaller as it is surrounded by a border).
Initially, instant film was sold on rolls, but later and current films are distributed in 8 or 10 pack sheets, and single sheet films for use in medium and large format cameras using a compatible back.
Integral film packs may incorporate a flat "Polapulse" electrical battery, which supplies power to systems in the camera, including exposure and focusing devices, electronic flash, along with a film ejection motor. The inclusion of a battery within the film pack itself ensures that a fresh battery is on hand with each new film pack.
Although the quality of integral instant film does not rival conventional film, peel apart black & white film, and to a lesser degree color film nearly approached the quality of traditional film. Instant film was used where it was bothersome to wait for a conventional roll of film to be completed and processed, such as documenting law enforcement evidence, or for health care and scientific purposes, and in creating photographs for other identity documents and passports, and just for snapshots to be seen immediately. Some photographers used instant film for test shots, just for a look at how a subject or setup looked before using conventional film for the final shot. Instant film is also used by artists to accomplish effects that are impossible to achieve using traditional photography, by manipulating the emulsion in the course of the developing process, or detaching the image emulsion from the base of the film. Instant film has been replaced for most uses by digital photography, which allows for immediate viewing of the the results on a display monitor or printed using inkjet, dye sublimation, home lasers or professional printers.
Instant film is distinguished for having had a wider available range of film speeds than other negative films of a similar era: instant film has been manufactured with ISO 4 to ISO 20,000. Present instant film formats typically feature an ISO between 80 and 3000.
Two companies make instant film: Fujifilm (Instax integral film) along with The Impossible Project for older versions of Polaroid cameras (600, SX-70, Spectra and 8x10).