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US 6,261,747 B1Granted
Black-and-white sepia toning kit and method for its use
AssigneeEastman Kodak Company
InventorsDavid J. Valvo, Hugh G. McGuckin, John S. Badger
Life of this patent
Estimating the term…
Abstract
A two-part sepia toning kit can be used to provide desired stable, warm sepia toned images in black-and-white photographic positive or negative materials such as black-and-white photographic prints. One part of the kit includes a silver bleaching composition comprising a hexacyanoferrate as the bleaching agent and halide ions in a molar ratio of at least 2.25:1. The second part is a toning composition that includes a sulfur-containing toning agent.
Claims13
A sepia toning kit comprising:
- a) a silver bleaching composition having a pH of from about 3 to about 8 when in aqueous form, and comprising at least 0.045 mol/l of a hexacyanoferrate as a bleaching agent and halide ions, the molar ratio of hexacyanoferrate ions to halide ions being from about 2.75:1 to about 4:1, and
- b) a toning composition having a pH of from about 7 to about 13 when in an aqueous form, and comprising at least 0.006 mol/l of a sulfur toning agent.
A method of providing a warm sepia toned image comprising:
- A) contacting an imagewise exposed, developed and fixed black-and-white photographic silver halide positive or negative material with an aqueous sepia silver bleaching composition having a pH of from about 3 to about 8 and comprising at least 0.045 mol/l of a hexacyanoferrate as a bleaching agent and halide ions, the molar ratio of hexacyanoferrate ions to halide ions being from about 2.75:
- 1 to about 4:1, and
- B) after washing said positive or negative material, contacting said material with an aqueous toning composition having a pH of from about 7 to about 13 comprising at least 0.006 mol/l of a sulfur toning agent.
Dependencies are inferred from the claim text.