METHOD OF PREPARING BROMO- AND BROMO-IODO-SILVER EMULSION WITH LAMELLAR MICROCRYSTALS Russian patent published in 1997 - IPC

FIELD: photomaterials. SUBSTANCE: method involves two-jet emulsification by addition at 55-85 C solutions of silver nitrate and potassium bromide or potassium bromide with 1.1-6.0 mol.% potassium iodide to the parent an aqueous gelatin solution containing potassium bromide at the rate (1.88-21.6) x 10^-6 mole/ml/min at silver nitrate molar concentration 0.3-1.6 M followed by solid phase isolation, washings, dispersing, chemical maturation with sodium thiosulfate and gold salt and spectral sensitizing agent addition. Before or after chemical maturation ω-chloroperfluoroenanthic acid potassium salt is added at amount (1×10^-4)-(1×10^-2) mole/mole Ag and also the following compounds: 1,1'-diethyl-2,2'-quinocyanine and 3,3'-di-(γ-sulfopropyl)-9-ethyl-4,5-benzo-4,5-(4'', 5''-dimethylthieno-[2'', 3''] -thiathiazolocarbocyanine betaine of the formula (I) and at amount (100-600) x 10^-6 mole/mole Ag or a mixture of compounds of the formula (I) and formula (II) , salts of 1,1'-diethyl-2,2'-quinocyanine and 3,3'-di-(γ-sulfopropyl)-9-ethyl-5,5'-dimethoxythiacarbocyanine at amount (50-300) x 10^-6 mole/mole Ag of each compound. EFFECT: enhanced light sensitivity at wavelength range 400-720 nm.