Diketopyrrolopyrrole pigment with high chroma

A process for the preparation of the highly opaque pigment form of the diketopyrrolopyrrole of formula ##STR6## having high saturation, characterized by a chroma C.sup.*.sub.ab of at least 45 in the CIELAB system in a full-shade plasticised PVC pressed sheet prepared in accordance with SIN 53775, part 2, and having a pigment concentration of 1% and a thickness of 1.00 mm, comprising reacting in a molar ratio of 1 to 2,

• a dicyclohexyl succinate, dialkyl succinate, monoalkylmonophenyl succinate or diphenyl succinate, in which the succinate's alkyl group(s) is/are selected from C.sub.1 -C.sub.18 alkyl and phenyl is unsubstituted phenyl or phenyl which is substituted by one or two halogen atoms, one or two C.sub.1 -C.sub.6 alkyl or C.sub.1 -C.sub.6 alkoxy groups, with a nitrile of the formula ##STR7## in an inert organic solvent and in the presence of an alkali metal or of an alkali metal alcoholate as strong base, at elevated temperature, to produce a pigment alkali metal salt, and subsequently generating a compound of formula I by protolysis of the resultant pigment alkali metal salt comprising adding, in a single portion, a suspension of said pigment alkali metal salt to water and an alcohol ROH, wherein R is C.sub.2 -C.sub.4 alkyl, in the temperature range from 65.degree. to 150.degree. C., and heating the pigment suspension for 30 minutes to 24 hours, and isolating a pigment of formula I.