Copper phthalocyanine containing at least 70% of the a -form is made by grinding the baked mass obtained by baking phthalonitrile in the presence of a copper salt and another inorganic salt which is water-soluble, inert and substantially free from water, without isolation of the crude copper phthalocyanine, at a temperature of not more than 80 DEG C. with benzine, benzene, toluene, xylenes, mixtures of xylenes, naphthalene, chloroform, chlorobenzene, butanol chloroethanol, phenol, cresol, acetone, formic acid, acetic acid, dimethyl formamide, acetonitrile, nitrobenzene, diphenylamine, anisole, butyl acetate or mixtures thereof, until the product contains at least 70% of a -copper phthalocyanine. Examples are given. Specifications 600,911, 685,582, 711,677, 712,380, 745,772, 761,308, 761,718 and 781,239 are referred to.
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