| 摘要 |
A method is disclosed of preparing a light-sensitive silver halide emulsion comprising the steps of: precipitating silver halide by means of a double-jet or a triple-jet technique in a reaction medium comprising colloidal silica as a protective colloid in the absence of any polymeric compound capable of forming hydrogen bridges with colloidal silica but in the presence of one or more onium compounds, said colloidal silica having an average particle diameter from 0.003 mu m to 0.30 mu m, the ratio by weight of onium compound(s) to silica being between 0.03 and 0.3 at every moment during precipitation and the ratio by weight of silica to silver halide, expressed as an equivalent amount of silver nitrate, being from 0.01 to 0.3 at the end of precipitation; desalting the reaction medium; redispersing the silver halide; and chemically ripening the said silver halide in the presence of an onium precursor compound together with a combination of compounds in order to generate sensitisation specks comprising silver, gold and selenium or silver, gold, selenium and sulphur.
|
