This invention provides a process for forming an acetoacetarylide-based pigment, comprising: (a) reacting a diketene with an amine to form an acetoacetarylide slurry; (b) separating the acetoacetarylide as a solid from the acetoacetarylide slurry; (c) adding the acetoacetarylide solid to a homogenizer; (d) homogenizing the acetoacetarylide in the presence of water and one or more additives to form an acetoacetarylide slurry; (e) pumping the acetoacetarylide slurry to a reaction tank; (f) adding an alkali or alkaline metal base to the slurry; (g) adding an acid to form a precipitate of the acetoacetarylide; and (h) reacting the precipitate with an azo compound, thereby forming a pigment. This invention also includes the pigments and intermediates thereto formed by the above processes.

A process for the preparation of organic pigments with enhanced fluorescence, which process comprises treating said pigments with a surfactant, and to the fluorescent organic pigments obtained by said process. The pigments according to the present invention can be used in marking applications, wherein durable fluorescence is required.

A process for the preparation of organic pigments with enhanced fluorescence, which process comprises treating said pigments with a surfactant, and to the fluorescent organic pigments obtained by said process. The pigments according to the present invention can be used in marking applications, wherein durable fluorescence is required.

A crystal growth inhibitor for azo pigments is disclosed. The crystal growth inhibitor comprises: (1) one or more sulfonated or carboxylated amines, and (2) one or more coupling components selected from the group consisting of acetoacetanilides, naphthanilides, pyrazalones and benzamidazoles; the coupling component being bonded to the sulfonated or carboxylated amines. The crystal growth inhibitor can be produced separately and added to the coupling component prior to the coupling reaction, or it can be formed in situ with the pigment. Preferably, an improved pigment according to the invention includes 2% to 5% by weight of the crystal growth inhibitor. Monoazo pigments including the crystal growth inhibitor have been shown to have greatly improved gloss, transparency and tinctorial strength.