In order to improve the application properties, in particular the rheological and coloristic properties, and the gloss behavior and the flocculation stability of dioxazine pigments in acrylic varnishes, the surface of the base pigment is modified by coating with sulfo-containing dioxazine derivatives, which in most cases have been converted into the corresponding metal salts, into specific salt-like derivatives derived therefrom or, if desired, into cyclic ammonium compounds. Such a modification of the base pigment, i.e. production of the pigment preparations according to the invention by adding the specific dispersant, can take place at the stage of the pigment synthesis, during a comminution process of the coarse-crystalline crude pigment, by addition to the already finely divided crude pigment in the course of a subsequent solvent finish treatment or by mechanical mixing of the two essential components, pigment and dispersant.