Patent ID: 6635413
Filing Date: 2003-10-21
Classification: G03C

Abstract:
A process for producing a lightsensitive silver halide emulsion comprising silver halide grains, wherein:the emulsion contains tabular silver halide grains in an amount of at least 50% of the total projected area of all the silver halide grains, the average iodine content of all the silver halide grains is at least 2 mol %, the tabular silver halide grains have at least 10 dislocation lines per grain, and each of the silver halide grains has a twin face spacing of 0.017 &mgr;m or less; and the process comprises (step 1) set forth below, and the process comprises a step of performing chemical sensitization so that a selenium sensitizer is added in an amount of 2.5Ã—10âˆ’6 to 5Ã—10âˆ’5 mol/mol silver and comprises a step of performing spectral sensitization: (step 1) performing the spectral sensitization in which a spectral sensitizer is added in the presence of 50 ppm or less of calcium, magnesium and strontium, followed by adding at least one water-soluble salt of a metal selected from the group consisting of calcium, magnesium and strontium, so that the concentration of calcium, magnesium and strontium becomes 100-2500 ppm; and then the chemical sensitization is started.