Silver halide emulsion, preparation method thereof and silver halide photographic material

A method of preparing a silver halide emulsion comprising silver halide grains containing at least 90 mol % chloride, 0.02 to 5.0 mol % bromide and 0 to 2.0 mol % iodide, based on silver and occluding at least one Group 8 metal compounds and at least one iridium compound, the method comprising the steps of:

• (i) forming the silver halide grains by mixing a silver salt and a halide salt in a dispersing medium and
• (ii) subjecting the silver formed silver halide grains to selenium sensitization,
• wherein in the step (ii), the selenium sensitization is performed in the presence of at least one selected from the group of a compound represented by formula (1), (2) or (3), a compound represented by formula (4), fine grains of at least one of silver sulfide, gold sulfide and silver-gold sulfide, and a compound represented by formula (S):
• R—SO2S—M formula (1)R1—SO2S—R2 formula (2)R3—SO2S—Lm—SSO2—R4 formula (3)
• wherein R, R1, R2, R3, and R4 are each an aliphatic group, an aromatic group or a heterocyclic group;
• M is a cation;
• L is a divalent linkage group;
• and m is 0 or 1;
• R11—(S)m1—R12 formula (4)
• wherein R11 and R12 are each an aliphatic group, an aromatic group or a heterocyclic group, or R11 and R12 combine with each other to form a ring;
• m1 is an integer of 2 to 6;
• 60
• wherein Q is an atomic group necessary to form a 5- or 6-membered nitrogen-containing ring;
• M1 is a hydrogen atom, an alkali metal or a cation group.