Surface morphology and composition of some "lustro" decorated fragments ofancient ceramics from Deruta (Central Italy)

Ten pottery sherds from excavations in the area around Deruta (Perugia, Ita ly), having the typical "lustro" decoration, were analysed to establish the ir chemical composition. particularly that of the "lustro", and to gain mon insight into the procedure followed in making this decoration. The fragmen ts, assigned to the 16th-17th centuries, were authenticated by thermolumine scence analysis (TL). Scanning electron microscopy-energy dispersive spectr ometry (SEM-EDS) was used to investigate the surface morphology and to dete rmine the chemical composition of both the decorated surfaces and some incr ustations. Fourier transform infrared spectroscopy (FTIR) was also used to characterise the incrustations. All fragments exhibited a similar chemical composition; the ''lustro'' is assigned to an ancient Spanish-Arabic formul a. The incrustations were attributed to different origins; the reddish, iro n-containing ones are due to residual lustro-paste, while the grey ones wer e produced by successive calcareous depositions. Reflectance fluorescence ( RF) measurements, applied in situ, showed that different and easily recogni sable emission signals are given by the "lustro", the blue design and the w hite glazed surface. (C) 2000 Published by Elsevier Science B.V. All rights reserved.