Portable and laboratory analytical instruments for the study of materials, techniques and environmental impacts in mediaeval mural paintings

Abstract

The present work aims to give an overview of the research published in the last 20 years on the study of mediaeval wall paintings using complementary analytical diagnostic techniques. The analyses carried out on fragments or in the field allowed the identification of the execution techniques and the chromatic palettes of the Middle Ages and uncommon materials, according to local availability, were sometimes identified. Portable analytical techniques have been very useful in the identification of raw material and degradation products, while in other cases they have allowed identifying particularly interesting areas, from a diagnostic point of view, where samples can be taken to complete the studies in the laboratory. Furthermore, this review aims to highlight the substantial change that has taken place in recent years in the study of wall paintings, mainly focused on the identification of degradation processes for preservation and restoration purposes. Indeed, particular attention has been paid to publications related to the study of the conservation state of wall paintings that tried to explain the decay pathways that occur because of the interaction between natural and anthropic environmental stressors (humidity, climatic variations, infiltration waters and environmental contamination) and the wall painting materials.