Halpine, S.M. 1996 An improved dye and lake pigment analysis method for high-performance liquid chromatography and diode-array detector.. Studies in Conservation 41: 76-94.

Notes: A new analytical method for characterizing a wide range of organic colorants is described. Using a high-performance liquid chromatograph (HPCL) equipped with a diode-array detector (DAD), this method uses a water/acetonitrile gradient with 0-1% trifluoracetic acid. This system has been used to analyze a wide variety of colorants, including Indian yellow and gamboge, as well as traditional lake pigments and dyes. Dye extracts of fibers taken from Gobelins furniture tapestries (National Gallery of Art, Washington DC) and lake pigments from Winslow Homer's watercolor box (Portland Museum of Art) were successfully analyzed using this technique. Cochineal and indigo were identified in both dye and lake pigment samples.