High contrast photographic emulsions

• US 3,393,073 A
• Filed: 04/16/1965
• Issued: 07/16/1968
• Est. Priority Date: 04/16/1965
• Status: Expired due to Term

• Current Assignee: Elisabeth Boyer Simone Leonie, Georges Reutenauer, Lucienne Preteseil Marie-Clair
• Original Assignee: Elisabeth Boyer Simone Leonie, Georges Reutenauer, Lucienne Preteseil Marie-Clair
• Inventors: GEORGES REUTENAUER, ELISABETH BOYER SIMONE LEONIE, LUCIENNE PRETESEIL MARIE-CLAIR
• Application Number:
  US04/448,887
• Time in Patent Office: 1,187 Days
• US Class Current: 430/569
• CPC Class Codes: G03C 1/04 with macromolecular additives; with layer-forming substances

Claims

1. A HIGH CONTRAST SILVER HALIDE EMULSION SELECTED FROM THE GROUP CONSISTING OF SILVER HALIDE EMULSIONS CONTAINING 60 TO 100 MOLE PERCENT CHLORIDE, 0 TO 40 MOLE PERCENT BROMIDE AND 0 TO 5 MOLE PERCENT IODIDE, AND SILVER HALIDE EMULSIONS CONTAINING FROM 40 TO 90 MOLE PERCENT CHLORIDE AND FROM 10 TO 60 MOLE PERCENT BROMIDE PREPARED BY FIRST PRECIPITATING A RELATIVELY CHLORIDE RICH SILVER HALIDE PRECIPITATE AND CONVERTING THE PRECIPITATE TO A BROMIDE ENRICHED SILVER CHLOROBROMIDE EMULSION BY THE ADDITION OF BROMIDE IONS, SAID EMULSION HAVING INCORPORATED THEREIN, IN A QUANTITY SUFFICIENT TO EFFECTIVELY REDUCE BLACK SPOTS, A WATER-SOLUBLE POLYMER SELECTED FROM THE GROUP CONSISTING OF POLY(N-ALKANOLACRYLAMIDE);

POLY(N-ALKANOLMETHACRYLAMIDE);

AND THE POLYMERS HAVING THE FOLLOWING STRUCTURAL FORMULA;