PHOTOGRAPHIC ELEMENTS

摘要

1347717 Photographic spectrally sensitized silver halide material EASTMAN KODAK CO 28 May 1971 [20 July 1970] 17747/71 Heading G2C A photographic material comprises a support and at least one layer containing an internal image silver halide emulsion comprising silver halide grains wherein the radiation sensitivity is predominantly internal to said grains and a spectrally sensitizing dye having a radiation absorption peak below 700 mp and a cathodic halfwave potential less positive than -I.OV present in a concentration which will lower the blue speed sensitivity of a surface sensitive control silver bromoiodide emulsion, wherein the halide is 6 mole per cent iodide, of the same average grain size at least 0À3 log E when developed for 3 minutes at 20‹C in developer D-19 (containing N-methyl-p-aminophenol sulphate, sodium sulphite (anhydrous), hydroquinone, sodium carbonate (monohydrate), KBr and water) and is sulphur and gold sensitized. The sensitizing dye may be used in a concentration which will provide at least 60% coverage of the total available surface of the grains. The sensitizing dye may be a cyanine, isocyanine, pseudocyanine, hemicyanine, merocyanine, oxonol or azacyanine dye. The silver halide grains mabe internally chemically sensitized and may have at least one metal dopant occluded therein e.g. bismuth, lead or iridium ions. The grains may have core and shell structures. Examples 5 describes a silver salt diffusion transfer process.