Illuminated manuscript analysis methodology using MA-XRF and NMF: Application on the Liber Feudorum Maior

Abstract

The determination of the composition of illuminated manuscripts' components is an important tool for the better understanding of their history, their origin and the procedures carried out for their elaboration, providing an insight into techniques and materials used in the times of their fabrication. By focusing on all three important aspects of an illuminated manuscript, which are their content, their decorative style and the composition of the materials used (CSM approach) a more complete vision of the manuscripts can be obtained, as the results of each field's studies complement each other. This article presents a methodology that combines the information obtained from single point measurements, Macro X-ray Fluorescence (MA-XRF) and Non-Negative Matrix Factorisation, evaluating the advantages and drawbacks each method presents, with an emphasis on the detection of minor signals and minor components and the interpretation of their contribution in the understanding the object and the artistic process carried out for its creation. The importance of adjusting the methodology according to each case's requirements is also indicated. The methodology has been applied to a late 12th century Catalan cartulary, the Liber Feudorum Maior, an exceptional non-religious cartulary, elaborated along more than one century, and which contains 76 miniatures painted in two different decorative styles. The information obtained from the different measurements has made it possible to establish not only a large part of the palettes used for the two painting styles but also determine small differences in the composition of the inks used to write the cartulary's text. Through this compositional study it has been possible to gain insight into the techniques used for the manuscript's elaboration, which could be indicative of the participation of multiple artisans.