E.i. Dupont De Nemours and Company

Joseph Anthony Sincius

Charles A Allen

William R Pangratz

Thomas Albert Bailey, Iii

A photographic developer containing hydroquinone, an auxiliary developer such as phenidone, and high sulfite is formulated using an organic base such as diethanolamine. This is useful for processing litho film in rapid access machine processors to produce high contrast line and half-tone dot images from films processed therein.

High contrast continuous tone developer and process of use

Lithographic developer in an automatic photographic film processor is replenished from at least two stable solution concentrates. As each quantity of lithographic film is processed predetermined amounts of the solution concentrates and water are mixed and immediately added to the developer. The solution concentrates, stable before mixing, contain all the constituents needed to replenish the developer solution to maintain activity at a desired level. The amount of each solution concentrate is predetermined from the concentration of each solution concentrate and the quantity and developer requirements of the film. The frequency of replenishment is predetermined from the usage pattern.

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Little Silver, NJ, United States of America

Joseph Anthony Sincius