The application of x-ray powder diffraction for the analysis of synthetic organic pigments. Part 1: dry pigments

This paper presents x-ray powder diffraction data for over 200 synthetic organic pigments. These pigments, most manufactured in the last 130 years, are frequently found in modern works of art. Their identification is of interest in the field of art conservation for the purposes of dating works of art as well as making conservators and curators aware of issues with lightfastness and solubility. Most classes of these pigments, including β-naphthol, Naphthol AS, mono- and di-arylide yellows, quinacridones, copper phthalocyanines, benzimidazolones, and perylenes give good diffraction data. Some pigments, including certain triarylcarbonium and some other metal containing pigments, especially aluminum containing pigments, were found not to diffract. X-ray powder diffraction is of great use in distinguishing polymorphs of pigments such as quinacridones and copper phthalocyanines.