| abstract |
The invention relates to a method for finishing an organic pigment, the pigment being dissolved or dispersed in mineral acid, and from the solution or dispersion the pigment being crystallizable by mixing it with an aqueous diluent in the presence of a condensation product of naphthalene sulfonic acid and at least one aliphatic aldehyde having 1 to 6 carbon atoms as a crystallization modifier, the product containing sulfonate groups, and subsequently the pigment being isolated as solid matter, characterized in that the crystallization modifier is present in the aqueous diluent. |