Preparation of thin tabular grain silver halide emulsions using synthetic polymeric peptizers.

摘要

A thin tabular Ag halide grain emulsion contg. at least 50 mol.% Br and in which grains less than 0.15 micrometres thick and with an aspect ratio greater than 8 account for more than 50% of the total projected grain area is prepd. by (i) nucleating the grains in the presence of a nucleation peptiser, and (ii) growing the grains in the presence of a growth peptiser. The nucleation peptiser is (1) a gelatino-peptiser, (2) a polymer of formula (I), or (3) a synthetic polymer of formula (II). The growth peptiser is (1) a gelatino-peptiser or (2) a synthetic polymer of formula (II), provided at least one of the nucleation and growth peptisers is the synthetic polymer of formula (II). In (I), x1 = 0-84; x2=0-84; y = 16-100; z = 0-10; R1 = H or CH3; R2 = H, CH3 or C2H5; L = alkylene or arylene of 1-10C; Q = CO2-M+ or SO3-M+; M = hydrogen, an alkali metal, NH4, NH3R1, NH2R1R2, NHR1R2R3 or NR1R2R3R4; R1 to R4 = 1-6C alkyl; Y = O or -NR-; R = H, CH3 or C2H5; R3 to R5 = H or 1-6C alkyl or R3+R4+R5, may complete a 5- or 6-membered ring which can include 0; X = Cl, Br, I, R6CO2, R6SO3, R6SO3 or R6SO2; R6 = an alkyl or aryl gp. with 1-10C. In (II), a = 0-15; b1+b2 = more than 10; R' = H or CH3; G = OH, NH-L-COOH or -NH-C(OH)H-COOH; L = alkylene or arylene with 1-10C, Z-N(R1)R1, -N(R1)(R1+X-)H or -N(R1)(R1+X-)R1; R1 = CH3 or C2H5; and X = as above. Also claimed is the tabular emulsion prepd. by the above process.