Scientific study of the gothic-renaissance altarpiece of Santiago church in Écija (Spain)

Abstract

This work reports the characterization of inorganic and organic materials used for producing the polychrome of gothic-renaissance altarpiece of 16th century. The study was carried out in the cross sections prepared from small samples. Combined use of optical microscopy, micro-FTIR spectroscopy, SEM-EDX and XRD techniques has proved to be valuable for the characterization of compounds detected within artworks studied. Gypsum and animal glue animal support, casein and egg, lead oxide, gold and bole layers, iron oxides, red lake, cinnabar, white lead, cobalt smalt, azurite, tin-lead compounds were found. Red colours were obtained by a mixture of vermilion (HgS), and red lead (Pb3O4). A red lake was also added in some cases. Hematite was used mostly for the obtaining of violet colour, mixed with azurite in some cases or with smalt in other ones. Green colour was obtained with a mixture of azurite and tin-lead yellow with hydrocerussite and calcite. These pigments and the kind of binders were indicative of original materials or at least not recent interventions. © 2015, Ecozone, OAIMDD.