Internal latent image type core/shell direct positive silver halide emulsion and its preparation

Abstract

Abstract PURPOSE:To enhance sensitivity and Dmax, to lower Dmin, and yet, to reduce occurrence of a double reversal negative image by deactivating a photographic additive in an emulsion with a deactivating agent till the end of forming core/ shell type silver halide grains or chemical ripening of the surface of the grains. CONSTITUTION:The substance to be deactivated is embodied by an S-contg. silver halide solvent, an S-contg. sensitizer, a dye, an S-contg. inhibitor, an adjuvant used in gold sensitization, etc., and it is a photographic additive serving as an effective sensitizer or a sensitizing adjuvant in forming silver halide grains when the shape or size of crystal is changed or allowed to be uniform and the core particles are chemically more sensitized in the stage of forming of silver halide particles. The substance is desirable that it is removed hardly from the emulsion by rinsing or controlling of pH like the dye or the S-contg. compd. which is adsorbed to the silver halide through the S atom above all. As the deactivator, whatever compds. capable of lowering or deactivating the action of the deactivatable substance and exerting no harm on the photographic characteristics, preferably, such as oxidants, can be used.

Inventors

• 👤 Hajime Murai
• 👤 朝 村井
• 👤 Hiroyuki Mifune
• 👤 御船　博幸
• 👤 Tatsuo Hioki
• 👤 日置　達男

Bibliographic Details