Photographic developing solution and use thereof in the high contrast development of nucleated photographic elements
AssigneeEastman Kodak Company
InventorsMichael D. Purol, Paul A. Zielinski, Donald L. Kerr
Life of this patent
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AssigneeEastman Kodak Company
InventorsMichael D. Purol, Paul A. Zielinski, Donald L. Kerr
Estimating the term…
An improved photographic developing solution is free of dihydroxybenzene developing agents such as hydroquinone, has a pH in the range of from 9.5 to 11.5 and comprises (1) an ascorbic acid developing agent, (2) an auxiliary super-additive developing agent and (3) a carbonate buffering agent in a concentration of at least 0.5 molar. The developing solution is broadly useful in black-and-white development but is most advantageously employed in a process for forming a high-contrast image utilizing a silver halide photographic element comprising a hydrazine compound which functions as a nucleating agent and an amino compound which functions as an incorporated booster. The developing solution is ecologically advantageous, exhibits excellent stability with respect to seasoning effects, and provides high speed and good upper scale contrast combined with a low level of pepper fog and a moderate degree of chemical spread.
An aqueous alkaline photographic developing solution that is free of dihydroxybenzene developing agents, said developing solution having a pH in the range of from 9.5 to 11.5 and comprising:
An aqueous alkaline photographic developing solution that is free of dihydroxybenzene developing agents, said developing solution having a pH of about 10.3 and comprising about 0.125 moles per liter of sodium sulfite, about 0.20 moles per liter of L-ascorbic acid, about 2 grams per liter of 1-phenyl-4-hydroxymethyl-4-methyl-3-pyrazolidone, about 0.90 moles per liter of potassium carbonate, about 0.20 grams per liter of benzotriazole and about 6.0 grams per liter of sodium bromide.
Dependencies are inferred from the claim text.