Abstract: A method for producing a silver halide emulsion in which grains having an aspect ratio of from 1.5 to 100 occupy from 75 to 100% of the total projected area of all grains comprising at least nucleation, ripening and grain growth processes in a dispersion medium solution containing water and a dispersion medium, wherein the dispersion medium solution contains low molecular weight gelatin having a molecular weight of from 1,000 to 70,000 at least during a nucleation process and chemically modified gelatin having a chemical modification rate of the amino group of from 15% to 100% at least during a grain growth process.

Abstract: A silver halide emulsion comprising at least a dispersion medium and silver halide grains is disclosed, wherein the silver halide grains comprise tabular grains having, as the main planes, {100} planes and having an aspect ratio (diameter/thickness) of 1.5 or more, in a proportion of 10% or more of the sum of the projected areas of all the grains, and the tabular grains each has at least one discontinuous halogen composition gap plane in their central part in such a way that the gap involves at least a difference of from 10 to 100 mol % in terms of the Cl.sup.- content or the Br.sup.- content or a difference of from 5 to 100 mol % in terms of the I.sup.- content between the adjacent layers. The reproducibility of the emulsion is good. The emulsion has high sensitivity, good graininess and good ability of forming high-quality photographic images.

Abstract: A novel silver halide emulsion containing a dispersing agent and silver halide grains is provided, characterized in that first tabular grains having a (100) plane as a main plane and an aspect ratio (diameter/thickness) of 1.5 or more whose shape on the main plane is a rectangular parallelogram having one to four corners non-equivalently missing account for 10% or more of all silver halide grains calculated in terms of projected area. In a preferred embodiment, 20% or more of the grains other than said first tabular grains calculated in terms of projected area is occupied by second tabular grains having a (100) plane as a main plane, an aspect ratio of 1.5 or more and the shape on the main plane of substantially a rectangular parallelogram.

Abstract: In a silver halide color photographic photo-sensitive material comprising a reflective support having thereon photographic structural layers comprising one or more silver halide emulsion layers, pH of a coating of the silver halide color photographic photo-sensitive material ranges from 4.0 to 6.5 and at least one of the silver halide emulsion on layers contains at least one mercapto heterocyclic compound and tabular silver halide grains having {100} planes was main planes and having a silver chloride content of not less than 80 mol %, the silver halide grains containing at least one selected from the group consisting of metal complexes of Fe, Ru, Re, Os, Rh and Ir.

Abstract: A silver halide emulsion is disclosed, comprising at least a dispersing medium and silver halide grains, wherein at least 60% of the total projected area of silver halide grains is occupied by tabular grains having a crystal defect for anisotropic growth which have a {100} face as a main plane and an aspect ratio (diameter/thickness ratio) of not less than 2.0, and the right-angled parallelogram enclosed with {100} faces at the edges of the tabular grains or a right-angled parallelogram formed by extending the {100} faces at the edges having a slenderness side ratio (a ratio of the length of the long side to that of the short side) of 1 to 6; and said silver halide emulsion is prepared in the presence of a compound A.sup.0 and/or a compound B.sup.0, wherein the compound A.sup.0 represents an organic compound having covalently bonded to an individual molecule thereof at least two molecules of an adsorbable agent which accelerates formation of a {100} face of silver bromide grains, and the compound B.sup.

Abstract: A silver halide emulsion comprises silver halide grains 35% or more of the total projected area of which are tabular grains having a {100} plane as a main plane and having an average aspect ratio of 1.3 to 7.9 which have been prepared via at least nucleation and ripening procedures. The emulsion is characterized in that said ripening procedure is conducted with substantially no NH.sub.3 present in the system. In a preferred embodiment, the ripening procedure is followed by the addition of fine silver halide grains substantially free of screw dislocation defects and having a diameter of 0.15 .mu.m or less that causes crystal growth. The nucleation is effected by the simultaneous addition of a silver salt and a halide salt solution to a dispersant solution. The resulting nuclei have a Br.sup.- content of 60 mol % or more. Cl.sup.- is present in said dispersant solution in an amount of 10.sup.-5 mol/l or more before the simultaneous addition.

Abstract: A process for producing a silver halide emulsion comprising tabular silver halide grains containing not less than 10 mol% of silver chloride and having {100} faces as major faces and an average aspect ratio of 2 or higher, which tabular silver halide grains are prepared by comprising rising temperature of a grain formation system after completion of (a) nucleation step and taking (c) grain growth step, which process comprises adding silver ions in an amount corresponding to at least 1 mol% of the total silver content to the silver halide emulsion at a stage after introduction of a halogen gap in the nucleation step (a) and before the grain growth step (c).

Abstract: Disclosed is a method for producing silver halide grains containing tabular grains having a thickness of from 0.02 to 0.3 .mu.m and an aspect ratio (diameter/thickness) of from 2 to 50 at a proportion of from 75 to 100% of the total projected area of silver halide grains, which comprises at least nucleation, ripening and growing steps in a dispersion medium solution consisting of water and a dispersion medium, wherein gelatin having the following characteristics (a) occupies from 30 to 100 wt % of said dispersion medium used in said growing step:characteristics (a)the relation between the number percentage of a chemically modified --NH.sub.2 group in the gelatin and the methionine content of the gelatin is in the region a.sub.1 depicted in FIG. 1.Also disclosed is a silver halide emulsion comprising at least a dispersion medium and silver halide grains produced by the above-described method.

Abstract: A silver halide photographic material is disclosed, which comprises a support having thereon at least one silver halide emulsion layer, wherein the swelling amount of the hydrophilic colloid layers including the light-sensitive silver halide emulsion layer and a protective layer coated on at least one side of the support is not more than 10 .mu.m in thickness and at least 60% of the total projected area of the total silver halide grains in at least one silver halide emulsion layer includes tabular silver halide grains having a Cl.sup.- content of at least 20 mole %, a {100} plane as the major plane, a thickness of 0.35 .mu.m or less, and an aspect ratio (diameter/thickness) of at least 2, and further a developing process for developing the above silver halide photographic material with a developer containing ascorbic acid or the derivative thereof is disclosed.

Abstract: There is disclosed a silver halide photographic material which is rapidly processable, high sensitive and small in variations in sensitivity between production lots of the photograhic material. The silver halide photographic material comprises a silver halide emulsion layer containing a cyan dye forming coupler, a silver halide emulsion layer containing a magenta dye forming coupler, and a silver halide emulsion layer containing a yellow dye forming coupler on a reflective support, wherein at least one layer of said silver halide emulsion layers comprises silver halide emulsion grains and compounds represented by the following general formulas (I) and (II), said emulsion grains being tabular silver halide emulsion grains having (100) planes as main planes and a silver chloride content of 90 mol % or more, and further the mean bromide ion content on surfaces of said emulsion grains is twice or more that of the whole emulsion grains: ##STR1## wherein the substituents are as defined herein the specification.

Abstract: An apparatus for producing a highly uniform mixture of a first solution with two or more solute-containing solutions comprises a reaction vessel with a porous member located therein. The porous member, whic may be a membrane or a plurality of fine tubes, is located within the vessel below the surface of the first solution. One or more solute-containing solutions are rapidly and uniformly introduced into the first solution through the porous member. The solute containing solutions diffuse rapidly into the first solution through the openings in the porous member, mixing evenly to produce a uniform composition.

Abstract: A silver halide emulsion at least containing a dispersion medium and silver halide grains, in which the grains of 20% or more of the total projected areas of all the silver halide grains are substantially octahedral grains as derived from cubic grains by deleting substantially two diagonal apexes of the eight apices of the cubic grain, the outer surface of the deleted site is a {111} plane, and the main plane (the maximum flat plane of the outer surface of the grain) is a {100} plane. Since the sites of forming chemically-sensitized nuclei are defined in the emulsion grains, dispersion of latent images formed is inhibited. The emulsion has a high sensitivity and has excellent reciprocity law failure characteristics, developability and formed image quality.

Abstract: A silver halide light-sensitive material containing at least silver halide grains, a dispersion medium, an antifoggant, and a hardening agent, wherein said antifoggant is an antifoggant having a reactive substituent capable of reacting with a functional group of the dispersion medium to form a covalent bond after adsorption on the silver halide grains and/or an antifoggant previously covalently bonded to the dispersion medium. The antifoggant is immobilized in a light-sensitive material while exerting its antifogging activity and is not therefore dissolved into a developing solution.

Abstract: A method for preparing silver halide emulsion grains by a crystal growth method comprising feeding fine silver halide grains to a reaction vessel containing seed crystals of a silver halide emulsion and dissolving the fine grains in the reaction vessel by Ostwald ripening to grow said seed crystals, wherein the fine grains are non-twinned crystal fine grains having substantially no twinning plane.

Abstract: A process for producing a light-sensitive silver halide emulsion comprising the steps of:(a) batchwise reacting in a first medium-sized reaction vessel an aqueous solution of a silver salt and an aqueous solution of a halide salt to form a silver halide emulsion comprising silver halide grains;(b) transferring said silver halide emulsion to a second medium-sized reaction vessel;(c) adding an aqueous silver salt solution and an aqueous halide salt solution or silver halide fine grains having a average diameter of at most 0.1 .mu.m to said silver halide emulsion in said second medium-sized reaction vessel and batchwise reacting said mixture to grow silver halide on said silver halide grains;(d) subsequently transferring the silver halide emulsion from said second medium-sized reaction vessel to a third medium-sized reaction vessel; and(e) batchwise subjecting said silver halide emulsion in said third medium-sized reaction vessel to at least one of desalting, chemical ripening or chemical sensitization.

Abstract: A silver halide light-sensitive material containing at least silver halide grains, a dispersion medium, an antifoggant, and a hardening agent, wherein said antifoggant is an antifoggant having a reactive substituent capable of reacting with a functional group of the dispersion medium to form a covalent bond after adsorption on the silver halide grains and/or an antifoggant previously covalently bonded to the dispersion medium. The antifoggant is immobilized in a light-sensitive material while exerting its antifogging activity and is not therefore dissolved into a developing solution.

Abstract: A process and apparatus for mass-producing a silver halide emulsion for photographic light-sensitive materials which includes carrying out the nucleation of the silver halide grains in a reaction apparatus having a middle capacity and carrying out physical ripening and/or the crystal growth in a reaction apparatus having a larger capacity than the middle capacity reaction apparatus. Another reaction apparatus having a larger capacity than the middle capacity reaction apparatus can be used to store nuclei formed in the middle capacity reaction apparatus before transfer of the nuclei to the other reaction apparatus having a large capacity in which physical ripening and/or the crystal growth are carried out.

Abstract: A silver halide photographic emulsion comprising silver halide grains is disclosed, wherein at least 60% of the total projected area of the silver halide grains is comprised of tabular silver halide grains having a central portion and an outer portion, of which the iodide content of the central portion is from 7 mol % to the solid solution limit, and which have two parallel twinned crystal planes.A method for the manufacture of the silver halide emulsion is also disclosed, which comprises the steps of nucleating the silver halide grains under conditions where the gelatin concentration in the reaction solution is set at from 0.1 to 20 wt %, the addition rates of the silver salt and the halide are set at from 6.times.10.sup.-4 to 2.9.times.10.sup.-1 mol/minute per liter of reaction solution, and the pBr value in the reaction solution is set at from 1.0 to 2.5, Ostwald ripening the nucleated grains, and then growing the thus ripened grains.

Abstract: A process or the preparation of a silver halide photographic emulsion is provided which comprises the addition of at least one pendant type spectral sensitizing dye containing as a substituent a compound having the effect of inhibiting fog at any time after the formation of silver halide grains, but before the completion of the chemical ripening process. In a preferred embodiment, the addition of said pendant type spectral sensitizing dyes is effected at any time after the formation of silver halide grains, but before former one second of the total time of the chemical ripening process. The pendant type spectral sensitizing dyes are compounds represented by the general formula (III) or (IV): ##STR1## wherein SSD represents a sensitizing dye portion; AF represents a compound portion containing a saturated or unsaturated 5- to 7-membered ring containing at least one nitrogen atom; L.sup.1 represents a divalent connecting group containing at least one of C, N, S and O; L.sup.2 has the same meaning at L.sup.

Abstract: There is disclosed a novel direct positive silver halide emulsion and a color diffusion transfer photographic film unit in which the above emulsion is used and which provides a high sensitivity and a low minimum density. The direct positive silver halide emulsion contains a core/shell type grain in which 60% or more of the projected area of all grains is shared by a monodispersed parallel twin crystal-containing type tabular grain having an aspect ratio of 1.5 or more, wherein the shell of the core/sell grain is formed by adding a silver salt in which at least 30 mole % of the silver salt is a non-twin crystal silver halide fine grain emulsion having an average grain size of 0.12 .mu.m or less.