Fuji Photo Film Company, Limited

Toru Sano

Munehisa Fujita

A method for producing a silver halide emulsion comprising high silver chloride tabular grains each having a chloride content of 50 mol % or more and having a major plane comprising a (111) face, which comprises a step for conducting nucleation of said grains substantially in the absence of a crystal phase controlling agent to form grains which have two twin planes parallel with each other and of which most of the surface are (100) faces, a step for ripening said grains by adding a crystal phase controlling agent which adsorbs to the (111) face or a mixture of a crystal phase controlling agent which adsorbs to the (111) face and a protective colloid to reduce the ratio of grains other than the grains having two or more parallel twin planes and then a step for growing with remaining tabular grains having a major plane mainly comprising a (111) face to form tabular grains having a major plane comprising a (111) face.

Method for producing silver halide emulsion

An internal latent image type positive silver halide emulsion has improved sensitivity reduction in low illuminance exposures. A color diffusion transfer light-sensitive material incorporates the emulsion and has reduced sensitivity reduction. The internal latent image type positive silver halide emulsion is prepared using a polymer having a repetitive unit derived from an ethylenically unsaturated monomer having at least one thioether structure on a side chain as a deflocculating agent to form silver halide grains and subjecting the grain surfaces to a chemical sensitization in the presence of a polymer having a repetitive unit represented by the following Formula (I): ##STR1## wherein R.sup.1 represents a hydrogen atom or a substituted or unsubstituted alkyl group and Q represents a group selected from the group consisting of groups represented by the following Formula (1) to Formula (4): ##STR2## wherein q represents an integer of 2 to 4; ##STR3## wherein R.sup.2 and R.sup.3 each independently represents a hydrogen atom or a substituted or unsubstituted alkyl group; ##STR4## wherein Z.sup.1 represents a group of atoms necessary to form a substituted or unsubstituted lactam ring, a substituted or unsubstituted oxazolidone ring, or a substituted or unsubstituted pyridone ring; and A represents a single bond, a --C(.dbd.O)-- group, or a group represented by the following Formula (3a): ##STR5## wherein B represents an --O-- group or an --N(R.sup.4)-- group, in which R.sup.4 represents a hydrogen atom or a substituted or unsubstituted alkyl group; and k represents an integer of 1 to 6; ##STR6## wherein A has the same meaning as A in the above Formula (3); D represents a single bond, an --O-- group or an --N(R.sup.5)-- group; m and n each represents an integer of 1 to 6, which satisfy the relationship of m+n.dbd.4 to 7, in which R.sup.5 represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a group represented by the following Formula (4a): ##STR7## wherein R.sup.6 represents a substituted or unsubstituted alkyl group.

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Kanagawa, Japan

Toru Sano