Summary. Assay of natural organic artists pigments is much more difficult than the detection of inorganic pigments. Thin-layer chromatographic methods are most advantageous for the lacquers since mixtures are frequently present. These show differing chromatographic behavior when separated on micropolyamide layers after acid cleavage of the lacquer with concentrated sulfuric acid. Uranyl acetate is superior to all previously known reagents for assay of hydroxyflavons and hydroxyanthraquinones on chromatograms. Sensitive color reactions sometimes help further in distinguishing very similar pigments: cochineal carmine forms a blue boric acid complex, whereas kermes carmine forms a violet boric acid complex. With uranyl acetate as trace reagent, 0.5 mug cochineal carmine and kermes carmine can be demonstrated. Soluble pigments can be distinguished by thin-layer chromatography on micropolyamide plates. IR spectra and specific dye reactions are suitable for distinguishing insoluble pigments. -- CCI