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Conventional photographic films and papers need to be chemically processed after they have been exposed in order to produce the desired negative or positive image. The general process is similar whatever the make of film or paper. The only obvious exceptions are a few proprietary makes such as Polaroid and other instant self-processing techniques; Kodachrome which cannot be processed except in Kodak laboratories. There are also a small number of relatively uncommon processes using dye decomposition technologies such as Cibachrome. Wikipedia does not have an article with this exact name. ...
It has been suggested that this article or section be merged with Film developing. ...
The Polaroid Corporation was founded in 1937 by Edwin H. Land. ...
Kodachrome (also known as Tripack) is a brand of color transparency (slide) film sold by Kodak. ...
Ilfochrome, formerly known as Cibachrome, is a C-Type positive-to-positive photographic process used for the reproduction of slides on photographic paper. ...
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. Latent Image can mean a few things: Latent image, a photographic term Latent image, a bondage magazine Latent Image, a fifth season episode of Star Trek: Voyager This is a disambiguation page: a list of articles associated with the same title. ...
Before processing the film must be removed from the camera and from its cassette or spool in a light-proof room or container.
Amateur processing
In amateur processing, 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 across the film's surfaces. The reel is placed in a specially designed light-proof tank where it is retained until final washing is complete. A camera is a device used to capture images, usually photographs, either singly or in sequence such as with video cameras. ...
A darkroom is a given space, usually a separate area in a building or a vehicle, that is made dark so as to allow photographers to use light-sensitive materials to develop photographs and film. ...
Commercial processing In commercial processing, the film is removed automatically or by an operator handling the film in a light proof bag from which it is fed into the processing machine. The processing machinery is generally run on a continuous basis with films spliced together in a continuous line. All the processing steps are carried out within a single processing machine with automatically controlled time and temperature. The film or prints emerge washed and dry and ready to be cut by hand. Some modern machines also cut films and prints automatically, sometimes resulting in negatives cut across the middle of the frame where the space between frames is very thin or the frame edge is indistinct, as in an image taken in low light.
The process Whether processing at an amateur or commercial level, the film is then treated in chemical baths. These baths are maintained at closely monitored temperatures and specific time periods. When making archival prints or prints of high quality, the minimum number of chemical steps are used. In particular additional stages such as hypo-eliminators or wash-aids are avoided because of uncertainty about the long term impact of such treatments on print stability and permanence. - The developer, which makes the latent image visible.
- A stop bath, which stops the action of developer - typically a dilute solution of Acetic acid. (Sometimes plain water is used for this step.) This neutralises alkaline developer carry-over and removes excess developer reducing cross contamination of the acid fixer.
- The fixer makes the image permanent and light-resistant by dissolving any remaining silver halides. The fixer is often referred to as "hypo".
- An optional "Hypo Clearing Agent" or washing aid bath, which renders fixer more easily removable by the washing process. Before the use of a washing aid, the majority of fixer is removed in a brief rinse in water. The wash aid helps remove the remaining hypo.
- Clean water wash to remove any fixer, as it is corrosive and can dissolve the elemental silver over time leading to staining and fading. The washing process can be shorter in time if a washing aid is used after the fixer.
- Final immersion in a film conditioner is commonplace. This is a solution of alcohol, wetting agents and formaldehyde in de-ionised water. This hardens the film surface, helps drying and eliminates drying marks from hard water.
- Film is then dried in a dust free environment, and finally (if roll sized film)cut, and put into protective sleeves.
It has been suggested that this article or section be merged with Film developing. ...
Stop bath is the second of three chemical baths usually used in processing traditional black-and-white photographic films, plates, and paper. ...
Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. ...
Photographic fixer is a chemical used in the final step in the photographic processing of film or paper. ...
Functional group of an alcohol molecule. ...
Surfactants, also known as wetting agents, lower the surface tension of a liquid, allowing easier spreading. ...
The chemical compound formaldehyde (also known as methanal), is a gas with a strong pungent smell. ...
Colour processing Colour negative processing and colour print processing is very similar. The principal difference is the inclusion of a colour developer in the development stage and the replacement of the fixer with a bleach-fix (Blix) which dissolves both the silver halides and the elemental silver leaving only a dye image.
Black and white reversal processing (to make black and white positives) has two additional stages. Following first development, the developing action is stopped, the film is then bleached to remove the elemental silver produced by development and it is then either exposed to light or chemically fogged prior to a second development. This allows the silver salts that were not exposed in the camera to be developed into silver forming a positive image. The remaining stages are as for normal processing.
In colour reversal processing the film is developed in a sophisticated black and white type developer (not a colour developer), the development is then stopped, the film is chemically fogged and is then treated in a colour developer. The remaining blix stage etc is the same as for colour negative film.
Further processing For black and white emulsions both negative and positive, further processing may react the silver with other elements such as selenium or sulfur to produce a more permanent image. In these cases the silver in the image is changed to silverselenide or -sulfite, which are more resistant to oxidising agents in the atmosphere. The fact that a successful selenium- or sulfidetoning depends on correct fixation and rigorous washing to remove residual thiosulfate also contributes to the longetivity of thusly toned emulsions. In other cases, the silver may be chemically bleached using a Potassium dichromate solution in strong mineral acid and the result washed film then re-processed to produce unusual coloured effects. Sepia, red and blue colours may be obtained in this way. If colour negative film is processed in conventional black and white developer, and fixed and then bleached with a Hydrochloric acid and potassium dichromate solution, the resultant film, once exposed to light, can be redeveloped in colour developer to produce an unusual pastel colour effect. Se redirects here. ...
General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ...
Potassium dichromate, K2Cr2O7 is used in oxidation reactions. ...
The chemical compound hydrochloric acid is the aqueous (water-based) solution of hydrogen chloride (HCl). ...
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