| 摘要 |
PURPOSE: To ensure high peak sensitivity to IR by incorporating a specified compd. as a sensitizing dye. CONSTITUTION: A compd. represented by formula I is incorporated as the sensitizing dye. In the formula I, each of L1 -L9 is methine, Z1 is a group of atoms substd. by -SR3 and required to complete a benzothiazole nucleus, etc., Z2 is a group of atoms required to complete a 5- or 6-membered heterocyclic ring, each of R1 and R2 is alkyl, etc., R3 is 1-4C alkyl, (m) is 1 or 2, (n) is 0 or 1 and X is a counter ion. The dye represented by the formula I is advantageously used so as to sensitize a photographic silver halide emulsion to IR and it can exhibit superior performance with respect to fog and shelf stability in many cases. High peak sensitivity to IR is ensured.
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