| 摘要 |
1,263,868. Radiographic films. FUJI PHOTO FILM CO. Ltd. 5 March, 1970 [7 March, 1969], No. 10640/70. Heading H5R. [Also in Division G2] A silver halide photographic emulsion contains at least one compound of the formula wherein R 1 , R 2 , R 3 and R 4 each represents H, halogen, alkyl, aryl, NO 2 , OH, alkoxy, substituted or unsubstituted amino group, or R 1 and R 3 or R 2 and R 4 may together represent a benzene ring, said compound(s) being present in amounts such that the ratio of the sensitivity to X-rays to the sensitivity to visible light of the emulsion is increased. The emulsion preferably contains 1À5 x 10<SP>-4</SP> to 1 x 10<SP>-2</SP> mole of said compound per mole of silver halide in said emulsion. The said alkyl group is preferably methyl, ethyl or butyl, the said halogen is preferably chlorine or bromine and said substituted amino group is preferably a mono- or di-alkylamino or an acylamino group.
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