The novel type tetramethinmerocyanine red sensitive dyes with benzopyran nucleus on the bridged chain is synthesized by alkaline heterocyclic compound,3-carboxylmethyl rodanine,and chromone.The visible absorption spectra in methanol and the sensitizing spectra in AgBr-AgI emulsion are determined.Among those dyes,the sensitizing dye used for laser image film is selected.The result shows that the photographic sensitivity is high and photographic properties are stable,especially the residual color is very little after processing.
