A piece of photographic film that has been exposed to light in a controlled manner must be developed before it can be used. Development does three things: it transforms the latent image into a visible image that can be seen, it makes the visible image permanent and resistant to deterioration with time, and it renders the film insensitive to light. Photographic paper is developed in a similar manner. Photographic film a sheet of plastic (polyester, celluloid (nitrocellulose) 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. ... In photography a latent image is formed when light (or in radiography, X-rays) acts on a photographic emulsion. ... Photographic paper is a type of heavy paper coated with light-sensitive chemicals. ...

(This article does not apply to Polaroid film, which uses a self-contained developing process.) Polaroid® (a trademark of the Polaroid Corporation) is the name of a type of synthetic plastic sheet which is used to polarise light. ... Instant film is a photographic film that is designed to be used in an instant camera. ...

The steps to black and white negative film developing are:

• The film is removed from the camera and wound onto a reel in complete darkness (usually inside a darkroom or a lightproof bag with arm holes). The reel holds the film in a spiral shape, with space between each successive loop so the chemicals may flow freely acrooss the film's surfaces. The reel is placed in a specially designed light-proof tank.
• The film is then treated with a series of chemicals:
  • The first of these is developer, which makes the latent image visible.
  • The second chemical is a stop bath, which stops the action of developer. (Sometimes plain water is used for this step.) It also helps to clean the developer residue off of the film to prevent contaminating the fixer.
  • The third chemical is called fixer. It makes the image permanent and light-resistant.
  • Fixer itself is slightly corrosive, so the film must be washed. Sometimes, it is then placed in a bath of a hypo clearing agent (and sometimes another material, such as selenium). It is then treated with a solution to prevent the appearance of hard-water stains, dried, and cut into strips of a convenient length.

In color negative processes the silver halide crystals present in the emulsion need to be removed. This is called bleaching. Bleaching may be done as an additional step or the bleaching agent, usually potassium ferricyanide, may be formulated in with the fixer. Bleaching may be skipped intentionally to create an optical effect on the film called Bleach bypass. A camera is a device used to take pictures (usually photographs), either singly or in sequence, with or without sound, such as with video cameras. ... A darkroom is a given space, usually a separate area in a building or a vehicle, for photographers to use light-sensitive materials to develop photographs. ... In film developing, photographic developer (or just developer) is a chemical that makes the image on the film visible. ... Stop bath is the second of three chemical baths usually used in processing traditional black-and-white photographic films, plates, and paper. ... Photographic fixer is a chemical used in the final step in black and white film or paper development. ... General Name, Symbol, Number selenium, Se, 34 Series nonmetals Group, Period, Block 16 (VIA), 4, p Density, Hardness 4790 kg/m3(300K), 2 Appearance grey, metallic lustre Atomic properties Atomic weight 78. ... A silver halide is one of the compounds formed between silver and one of the halogens, notably silver bromide (AgBr), silver chloride (AgCl) and silver iodide (AgI). ... In chemistry, to bleach something generally means to whiten it or oxidize it. ... Potassium ferricyanide (K3Fe(CN)6), molecular weight:329. ... Bleach Bypass is a film technique used in such movies as Seven or The Crow. ...