Photographic developer
(Also called developer ) The developer liquid has to make the task of the latent images of an exposed film visible (see photo emulsion).
Developers are reducing agents to react differently to the exposed and unexposed silver halide. In the development process, the developer is oxidized, i.e., it emits electrons which are absorbed by the silver ions. These are then to metallic, so visible, silver.
This reaction takes place especially in those places where light has fallen to a silver halide crystal.
In the subsequent fixing, the excess residues are washed.
In paint films bind color coupler during development to the silver, which is then removed by bleaching of the emulsion, so that only the dyes are contained in the film.
Black and White Developer
The developer substances different chemicals are used, the choice affects the outcome especially in the black and white films. Reducing agents commonly used are p-aminophenol that is marketed by Agfa Rodinal, hydroquinone, which is contained in Neofin the manufacturer and Tetenal Kodak TMax, and p- methylaminophenol sulfate, which is also included in Neofin and Ultrafin. Almost all black and white developer containing these or combinations of these reducing agents. The developers often contain preservatives, acids or bases for adjusting the pH. Alternative developers like Caffenol exist, however, from eco-friendly materials that are available in any supermarket, and deliver high amazing results. The development of black and white papers usually the same substances are used in different concentration.
Color developer
Color developers are very complicated recipes. For today's negative color films exclusively on the development process C-41 is used in practice, for slide films of Process E- 6 as well as for color papers, the development process RA- fourth
Holographieentwickler
In holography different developers are used which have different compositions depending on the type of the recording material and hologram type. Many of these developers are based on pyrogallol, Metol, or urea. Additives include sodium sulfite or sodium carbonate. To some extent, also worked with commercial photo developers that are easy to handle but not in many cases lead to optimal results.
- Photo Lab Technology