The coloring matters from 18 sources yelding quinonoid products are tabulated. The experimental methods for identification used in the author's laboratory are reviewed. Microchemical tests are insufficiently specific. Visible, fluorescent and infrared spectroscopy have all been used. Thin layer chromatography is preferred over paper chromatography, but suitable operating conditions for both are tabulated for various materials. Gas chromatography has also been used. Most of the preceding methods can be used for colorants on textiles, but samples size considerations with lakes from paintings usually preclude all but thin layer chromatography.