Raman spectroscopic database of azo pigments and application to modern art studies

The application of Raman spectroscopy to the examination of ancient art and the identification of mineral pigments used in antiquity has been demonstrated successfully hitherto. However, the examination of modern objects of art is hampered by the absence of a spectral library database of relatively modern organic pigments and dyestuffs, of which there are a large number. Azo pigments provide an example historically of a class of synthetic organic pigments which have been adopted by artists. The Raman spectra of 21 azo pigments were analysed and a protocol was established for their identification. Using this database, two azo pigments from 1 µg samples of 20th century paintings attributed to Picasso and Appel were characterized. Copyright © 2000 John Wiley & Sons, Ltd.