PHOTOSENSITIVE SILVER HALIDE EMULSION, ITS PREPARATION AND SILVER HALIDE PHOTOGRAPHIC SENSITIVE MATERIAL USING SAME

摘要

PROBLEM TO BE SOLVED: To obtain a silver halide photographic emulsion having high sensitivity by adding an anionic spectral sensitizing dye substantially in the absence of a polyvalent cation which forms a slightly soluble salt with the dye, adding the cation after the sufficient adsorption of the dye and then starting chemical sensitization. SOLUTION: An anionic spectral sensitizing dye is added to an emulsion substantially in the absence of a polyvalent cation which forms a slightly soluble salt with the dye. After the sufficient adsorption of the dye, the cation is added and then chemical sensitization is started to prepare the objective emulsion. By this method, the inter-grain distribution of dye adsorption is improved and the chemical sensitization is efficiently carried out. The polyvalent cation is preferably at least one of calcium, magnesium and strontium ions.