Gilding materials and techniques: Comparison between altarpieces and their sculptures-a case study

Abstract

We aim to present an analytical study of the materials used in two 17th-18th centuries sculptures-Santa Bárbara and Santa Rita de Cássia-and in the altarpiece where they once stood. All the pieces belong to the Church of Nossa Senhora das Mercĉs in Évora, although today the two sculptures are in the Museum of Évora. The main purpose is to compare the materials and the techniques used in the execution of the gilding and polychrome processes in the three objects. The study is focused on ground layers, gold leaf and polychrome layers. The stratigraphic analyses were performed using optical microscopy on cross-sections and the materials characterization of the different strata resorted to scanning electron microscopy coupled with energy dispersive X-ray spectrometry and to micro-Raman spectroscopy. The results show that the materials and techniques used in the three works of art are very similar and are consistent with the epoch's treatises suggestions.