Preparation method of regular silver (halide) bromide or silver bromoiodide light-sensitive emulsions and material comprising said emulsions

US5476761A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Ann Verbeeck · Begijnendijk, BE
• Hubert Vandenabeele · Mortsel, BE

Key dates

• Filing date: Sep 12, 1994
• Grant date: Dec 19, 1995
• Expiry date: Sep 12, 2014

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S430/167
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method is disclosed to prepare a light-sensitive regular silver bromide or silver bromoiodide emulsion, wherein said method comprises the following the steps: PA1 precipitating silver bromide or silver bromoiodide 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) comprising gelatin or its derivatives capable of forming hydrogen bridges with colloidal silica, except for polythioether compounds, but always in the presence of an onium compound, except for an ammonium compound, wherein the ratio by weight of said colloidal silica to the said onium compound(s) is between 3 and 30, and, optionally, in the presence of a crystal growth modifier, PA1 controlling the nucleation and growth steps by means of variable flow rate(s) of the aqueous solutions of silver nitrate and halide salts and/or by means of constant pAg-values during the 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, PA1 desalting the reaction medium and redispersing the silver hal…