Monochrome developer formulae in general use

Many thousands of different developer formulae have been published and a great number of different formulae are still in general use. Nevertheless, the basic types of formulae in use today are relatively few in number. Unfortunately, there is no generally agreed method of classifying developer formulae. At one time developers were classified according to the developing agents they contained; this terminology persists to a limited extent. Thus, developers are still termed MQ and PQ for metol-hydroquinone and phenidone-hydroquinone respectively.

Developers are also classified according to their action (fine-grain, low-contrast, high-contrast, acu-tance etc.) or according to the materials for which they have been formulated (print, colour-negative, X-ray, lithographic, etc). In addition to this confusing and overlapping terminology, developers are also known by a number of trade names or code numbers. Kodak: D-76, HC-110, Microdol-X, Technidol LC; Ilford: ID-11, Ilfotec HL, Ilfosol-S, Microphen, Perceptol; Agfa: Atomal FF, Refinal, Rodinal, Studio-nal Liquid; Fuji: Fujidol. All are trade names of some representative developers from manufacturers of sensitized products. There are also many other named developers from specialist manufacturers of processing chemicals who provide developers for processing a wide variety of films.

For convenience, developer formulae may be classified into various types which combine the type of developer, its action and the material for which it has been designed, thus avoiding the use of uninformative trade names.

• Universal: Suitable for developing all types of materials such as roll film, sheet film, 35 mm film, papers. However, although such developers are very convenient because of their universality, it is better to select a developer that is specially formulated for the material concerned.

• Fine-grain: For yielding negatives such that graininess is optimized in the prints. These are particularly suited for the development of 35 mm films which may require a high degree of enlargement.

• Low-contrast: Designed to give negatives of very low contrast, either for recording scenes of exceptionally high contrast, or for developing films which are inherently high in contrast to give negatives that can be printed with a full range of tones.

• High-contrast: For developing line, X-ray, aerial films, i.e. where it is necessary to produce a contrast that is higher than normal.

• Extreme-contrast: Also termed 'lithographic'. Developers formulated for use with lithographic films, to give the extreme contrast as required in the production of line and half-tone screen images for photomechanical work.

• Acutance (high-definition): Specially formulated for maximizing edge effects for increased image definition.

• Paper or print: Specially formulated for developing prints in dishes or for machine-processing of prints.

• Colour (chromogenic): Colour-negative developers used for the development of monochrome films that have dye images rather than images of metallic silver (Ilford XP-2).

• Concentrated: For one-shot use. The highly concentrated developer is diluted by a large amount, used once only and then discarded.

The most widely used developers are based on mixtures of metol and hydroquinone (MQ), and phenidone and hydroquinone (PQ). Although other combinations of developing agents are used, for general photography nothing has been found to equal MQ and PQ mixtures in all-round efficiency and flexibility.

Continue reading here: Colour chromogenic developers

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