developing

…came from experience with a developer known as pyro (pyrogallol), once very popular with still photographers. A negative developed with pyro developer has not only a silver image but also a brown stain. Study of the process showed that the stain was caused by oxidation products given off locally by…

During development (in a darkroom) the silver salt crystals that have been struck by the light are converted into metallic silver, forming a visible deposit or density. The more light that reaches a given area of the film, the more silver salt is rendered developable and…

…support, it was impossible to process photographic images by any means other than immersion in solutions contained in a shallow pan or tray or by dipping into a tank of solution. Such tank and tray processing remains important but is now being supplanted by the use of automatic film-processing machines.…