This invention relates to a process for preparing perylene pigment compositions by reaction of(a) a perylene tetracarboxylic compound;(b) about 0.01 to about 20% by weight, relative to the perylene tetracarboxylic compound, of a non-pigmentary cyclic anhydride or imide of formula (I) ##STR1## wherein W is O or NR.sup.1 (where R.sup.1 is hydrogen, a metal, or optionally substituted alkyl, cycloalkyl, aralkyl, or aryl), R.sup.2, R.sup.3, and R.sup.4 are various combinations of substituents and/or fused-on rings, and the dotted line is an optional double bond representing R.sup.2 --C.dbd.C--R.sup.3 ;(c) ammonia or a primary alkyl, aralkyl, or aryl amine; optionally in the presence of(d) a solvent and/or(e) one or more dispersants.