Method to spectrally sensitize tabular silver halide grains

摘要

A method has been disclosed for preparing a tabular silver halide emulsion wherein tabular silver halide grains having an average aspect ratio of at least 2:1, an average crystal diameter from 0.3 mu m to 3.0 mu m and an average thickness of less than 0.50 mu m account for at least 50 % of the total projective surface area of said grains, said method comprising the steps of precipitating, spectrally sensitizing and chemically ripening said grains, characterized by spectrally sensitizing by adding to the emulsion grains before chemically ripening at least one J-band aggregating spectrally sensitizing dye and at least one non-J-band aggregating dye. A light-sensitive silver halide emulsion having at least one J-band aggregating dye and at least one non-J-band aggregating dye comprising said tabular grains has also been disclosed as well as a light-sensitive silver halide photographic X-ray material comprising a support, at least one hydrophilic colloid layer on at least one side of said support and one or more photosensitive layer(s) comprising the said silver halide photographic emulsion and a radiographic screen-film combination comprising at least one X-ray intensifying screen in operative association with the said material.