Process for preparing a photographic emulsion comprising silver halide grains with high silver chloride content
US6218098A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1999 |
| Grant date | Apr 17, 2001 |
| Priority date | — |
| Expiry date | Sep 2, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2001/03541
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process for the preparation of a high chloride silver halide grain emulsion in which at least 50% of the projected area of the emulsion grains is accounted for by cubic grains, said process comprising: PA1 i) precipitating an intermediate emulsion containing high chloride cubic nuclei having an average edge length less than or equal to 0.07 .mu.m, by adding to an external continuous reactor at least one silver salt aqueous solution, a chloride salt aqueous solution and a hydrophilic colloid aqueous solution, in conditions so that (Qgel*Tgel)/(Qag*CAg) is more than 100, wherein Qgel is the flow rate of the hydrophilic colloid aqueous solution, Tgel is the hydrophilic colloid content of the hydrophilic colloid solution (g/l), QAg is the flow rate of the silver salt aqueous solution, CAg is the silver concentration of the silver salt aqueous solution (mole/l) and is comprised between 0.01 and 5 moles/l, the average pCl in the external reactor being between 1.7 and 3.5, PA1 ii) continuously transferring the intermediate emulsion containing the cubic nuclei from the external continuous reactor to a storage vessel, PA1 iii) stabilizing the nuclei by the addition of a growth inhibitor i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.