The conservation of medieval manuscript illuminations: A chemical perspective

Illuminated manuscripts are the most abundant and well-preserved surviving medieval cultural artefacts. Created to contain sacred texts, their visual structure allows the reader to identify divisions and delight in their beautiful ornamentation and iconography. Western European manuscripts were written on parchment, which was the main writing support in the Middle Ages prior to the rise of paper production in the fourteenth-fifteenth centuries. Highly functional, durable animal skins were also used in medieval bookbinding (covers) and have been crucial in the preservation of the illuminations. These illuminations make wonderful use of form and colour. This chapter focuses on recent advances in the molecular characterization of these colours, used in medieval manuscripts produced by Western Europeans, and the challenges inherent in analysing materials that are intrinsically heterogeneous. We then discuss how molecular characterization may reveal conservation conditions and extend our analysis to parchment and iron gall inks. Finally, we address the challenges and possibilities for this flourishing field of research. In short, we show in this chapter how analytical methods are used: - To understand how medieval illumination colours were made and what palette defines them; - To predict original colours and to understand why certain colours have remained in excellent condition, preserving both adherence and luminosity, while others have changed over the centuries; - To assess deterioration (paints, parchment, writing inks) with the goal of determining what potential restoration measures could be taken, after careful consideration.