Multi-analytical identification of a painting workshop at the Roman archaeological site of Bilbilis (Saragossa, Spain)

Abstract

Abstract In this work, we studied wall painting fragments from the exedra in Domus 1 and tablinum in the House of the Lararium in Bilbilis, an ancient Roman town in the Spanish province of Saragossa, in order to find whether the two paintings were produced by the same artisan workshop and to identify the painting technique used. For this purpose, we examined the paint and mortar layers of the fragments by using various semi-destructive instrumental techniques including X-ray diffraction (XRD), X-ray fluorescence (XRF) and Raman spectroscopies, and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS). The fragments used were representative of the colours in each paint, which included black, yellow, green, burgundy, beige and orange. Raman spectroscopy in combination with XRF analyses allowed the chemical composition of each pigment to be unequivocally established. All pigments (carbon, yellow ochre, a glauconite–Egyptian blue mixture, hematite, aragonite and red lead) were typically used in Hispania. Based on the Raman and XRD results, the mortars were obtained in the traditional manner by mixing sand and lime.