Patent ID: 6238854
Filing Date: 2001-05-29
Classification: G03C

Abstract:
Black-and-white silver halide developer composition, said composition comprising, besides one or more developing agent(s), agent(s) preventing oxidation thereof and agent(s) providing pH buffering,at least one silver complexing agent, characterized in that said silver complexing agent has a silver complexing stability ratio of at least 70%, wherein said silver complexing stability is determined after dissolving 50 mg of the said complexing agent in 200 ml of said developer composition, adding thereto under constant vigorous stirring 74 ml of a solution of silver nitrate having a concentration of 0.0005 moles/liter, adding over a period of 30 minutes said solution to the said developer solution thereby providing a total amount of added silver expressed as an equivalent amount of silver nitrate of 15 mg/l, leaving said solution unstirred in order to provide an equilibrium state between formed precipitate and supernatant developer liquid and measuring the silver content in the said supernatant liquid after 3 weeks; wherein said complex stability ratio is calculated as ratio of silver content in supernatant liquid to total amount of silver added; andat least one agent preventing silver dissolution, characterized in that said agent preventing silver dissolution, if present in an amount of 50 mg/l of developer, makes silver content of the developer decrease in an amount of more than 50% versus in the absence thereof, without loss in speed in an amount of more than 0.10 log Exposure after processing in said developer composition.