Preparation method of regular silver halide light-sensitive emulsions comprising silver halide crystals rich in chloride and material comprising said emulsions
US5543284A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 6, 1995 |
| Grant date | Aug 6, 1996 |
| Priority date | — |
| Expiry date | Apr 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/07
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method is disclosed to prepare a photographic light-sensitive silver halide emulsion, containing regular silver halide crystals rich in chloride having a predictable size distribution and wherein said method comprises the steps of precipitating silver halide crystals rich in chloride by means of the double-jet or triple-jet technique in colloidal silica having a particle size from 0.003 .mu.m to 0.30 .mu.m as a protective colloid in the absence of any polymeric compound(s) capable of forming hydrogen bridges with colloidal silica, but always in the presence of an onium compound, wherein the ratio by weight of said colloidal silica to the said onium compound(s) is between 3 and 75; controlling the nucleation and growth steps by means of variable flow rate(s) of the aqueous solutions of silver nitrate and chloride containing salts, and/or by means of constant pAg-values during said steps in the vessel in order to determine the number of nuclei quantitatively in the nucleation step and to avoid renucleation in the growth step, and wherein at every moment the total amount of monovalent ions of the electrolyte present during both steps is less than 1.0 molar; desalting the reaction me…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.