Analytical study of Roman and Arabic wall paintings in the Patio De Banderas of Reales Alcazares’ Palace using non-destructive XRD/XRF and complementary techniques

A portable XRD/XRF system and complementary laboratory techniques were employed to improve the knowledge of the procedures used to create Roman and Arabic wall paintings. Integrated physico-chemical investigations were conducted on fragments of artworks collected from the archaeological excavation of the Patio de Banderas in the Reales Alcazares’ Palace of Seville (Spain), and a comparative study on the pigments from both historical periods was performed. As a result, pigments such as vermilion, red ochre, yellow ochre, green earth, Egyptian blue, carbon and phosphor-based black pigments were detected in Roman samples; however, in the Arabic fragments, only haematite was observed. In addition, the size and shape of the particles of the wall paintings were studied with an XRD 2-dimensional detector and SEM-EDX.     

Technological Features of Roman Terra Sigillata from Gallic and Italian Centres of Production

Technological features of sherds of Roman terra sigillata were studied. The sherds analysed represented products of workshops which were most probably located in Gaul, central Italy, north-west Italy and the plain of the river Po. Equivalent firing temperatures were estimated by colour measurement, X-ray diffraction and thermal expansion measurement; in addition, the chemical and morphological features of the red sintered slips were investigated using scanning electron microscopy coupled with energy dispersive X-ray microanalysis. The combined results suggest that, relative to northern Italian products,terra sigillata from Gaul and central Italy was made by potters who were more successful in modifying slip composition and controlling firing temperature to obtain highly sintered slips. Northern Italian potters seem to have worked their clays less successfully and fired them at temperatures which were too low to overcome the limited presence of fluxes in the slip.