Azo pigments

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Azo pigments are solid, colorless particles (typically earths or clays), which have been colored using an azo compound. The azo compounds are highly colored organic molecules. Their light absorption is too great to be on their own (and their price would inhibit this): this would appear as very dark. The full brightness and tone of the color comes into its right when diluted. In order to be able to be used in paints, solid particles are necessary to convert the azo colorant into a pigment. The azo pigments form an important class of pigments in all kinds of paints including artist's paints. They have excellent coloring properties, mainly in the yellow to red range, and lightfastness. The lightfastness depends not only on the properties of the organic azo compound, but also on the way they have been adsorbed on the colorless pigment carrier. Azo pigments are advantageous because they are non-toxic.