Method for preparing physical development nuclei for use in silver salt diffusion transfer process

摘要

According to the present invention, a method is provided for preparing physical development nuclei for use in silver salt diffusion transfer processing, said physical development nuclei comprising a heavy metal sulphide, said method comprising the steps of: precipitating said heavy metal sulphide by bringing a water soluble heavy metal compound in reactive association with a water soluble sulphide in an aqueous liquid and said precipitation being carried out in the presence of a hydrophilic polymer so as to disperse said heavy metal sulphide, said hydrophilic polymer comprising a heterocyclic group, characterized in that said heterocyclic group is present in a recurring unit of said hydrophilic polymer, said recurring unit being comprised in said polymer in an amount between 0.1 mol% and 5 mol%.