The examination of the Book of Kells using micro-Raman spectroscopy

The Book of Kells, Trinity College Dublin MS 58, is one of Ireland's greatest cultural treasures, and as such all aspects of its production have attracted academic attention. Until recently, studies of its dyes and pigments have relied exclusively on techniques such as visual and optical microscopic and spectroscopic examination, and comparison of the appearance of the pigment with specimens prepared using ancient or medieval recipes. These studies have yielded interesting results, but, due to the limitations of the examination techniques, they have remained incomplete and somewhat speculative. This article presents the results of a pigment analysis that took place between 2004 and 2006 using micro-Raman spectroscopy. In total, 681 sites over the 4 volumes of the Book of Kells were analysed using 2 separate laser wavelengths (632.8 and 532 nm), making this the most extensive Raman spectroscopic investigation of a single medieval manuscript. In this article several pigments are identified, in particular, blue (indigo), red-orange (red lead), yellow (orpiment), green (vergaut), black (carbon and iron gall ink), and white (gypsum). In addition, purple (orcein) is also discussed. Copyright (C) 2009 John Wiley & Sons, Ltd.