SILVER HALIDE PHOTOGRAPHIC SENSITIVE MATERIAL HAVING IMPROVED SPECTRAL SENSITIZING SENSITIVITY

摘要

PURPOSE:To obtain a silver halide photographic sensitive material having high sensitivity by providing (nn1) crystal faces to the surface of silver halide particles and spectrally sensitizing the same with a sensitizing dye having the reduction potential lower than -1.2V. CONSTITUTION:All the outside surfaces of the silver halide particles are constituted of the (nn1) crystal faces. 24 pieces of the equiv. crystal faces expressed as the (nn1) crystal faces exist when the side faces of the particles formed in such a manner are viewed from the directions of straight lines b1 and b2. The crystal with all the outside surfaces constituted of the (nn1) crystal faces, therefore, takes the form of a trisooctahedron and the respective surfaces have an obtuse-triangular shape in which two kinds of vertexes exist. More specifically, the vertex is constituted of the 6 vertexes equiv. to a1 shown in the figure and the 8 vertexes equiv. to b1. The 8 planes border each other at the vertex a1 and the 3 planes contact each other at the vertex b1. Two kinds of sides exist as well; 24 pieces of the sides equiv. to the side a1 and b1 are formed and 12 pieces of the sides equiv. to the sides a1 and a2 are formed. The crystal faces entirely different from the ordinary (111), (110) crystal faces are thus constituted and the sensitivity is improved.