The Romanesque Portal of the abbey-church of Cluny: study of polychromy

The Romanesque abbey of Cluny was almost entirely destroyed after the French Revolution. As part of the Cluny 2010 initiative (the commemoration of the 1100th anniversary of its foundation), the Gunzo project leads the research and promotion of the heritage of Cluny thanks to digital technologies and virtual reality. This interdisciplinary team is working on the creation of a digital model of the Cluny abbey according to the latest scientific research, including the archaeological excavations and the study of the documentary sources. Samples of polychromes and gildings were collected from selected lapidary fragments which are representative of different parts from the Romanesque Portal (jambs, lintel, tympanum and archivolts). Pigments and gildings were analysed using scanning electron microscopy (SEM), energy-dispersive Xray spectrometry (EDS) and micro-Raman spectrometry. The physicochemical analyses point up the use of relatively expensive materials, such as gold leaves, lapis lazuli or cinnabar. Moreover, some blackish layers were identified as altered leaves of tin. The palette and abundance of metallic leaves should reflect the prestige of the abbots of Cluny.