PROCESS FOR PRODUCTION OF AN AZOMETHINE PIGMENT

A process for the production of a compound of the formula: in pigmentary form having a mean particle size not exceeding 0.3 microns, comprising:a) reacting .beta.-naphthol with chloroform in an alkaline medium, using a sufficiently slow rate of addition of chloroform that the reaction mixture, after initially assuming a deep blue colour and then turning green, maintains this green colouration until the addition of chloroform has been completed;b) reacting the alkali metal salt of 2-hydroxy-1-naphthal-dehyde from step a) with 2-aminophenol to produce a ligand of formula: IIc) metallising the ligand of formula II with an aqueous solution of a coppering agent, and isolating the complex metal pigment of formula I. - 1a