LAUSR

Abstract Synthetic organic pigments have been used in works of art for well over 130 years. During this time, many have been introduced and some have been removed from production. Historical pigments are synthetic organic pigments that are no longer commercially produced. Because of their limited range of time of commercial availability, they are of particular interest to art historians and conservators because, if identified in a painting, they can provide valuable information about artist materials and methods. In addition, once the pigment has been identified, conservators will be better informed in treatment and display conditions of the works of art. A number of azo-pigments are historical, and many of these have not been characterized by modern analytical techniques. We synthesized a series of azopigments, specifically members of the pigment classes: arylide (Hansa) yellow, diarylide yellow and oranges,as well as the red Naphthol AS. The pigments were characterized by Raman spectroscopy and Laser Desorption Ionization Mass Spectrometry (LDI-MS). The pigments synthesized and characterize include: PR7, PR11, PR18, PR19, PY49, PY203, PY113, PY124, PO14and PO15.