Characterization of lead glazed potteries from Smyrna (Izmir/Turkey) using multiple analytical techniques; Part I: Glaze and engobe

Eighteen lead glazed potsherds from the Ayasuluk region (Smyrna) were characterized in order to have detailed knowledge of their production technology. Micro-Raman and scanning electron microscopy (SEM) with the combination of an energy dispersive X-ray spectrometer (EDX) was used for their characterization. EDX analysis of the glaze layers showed that lead oxide was used as a fluxing agent for the production of most of the potsherds. Microstructural characteristics such as rod-shaped crystals at the interaction layers, residual quartz crystals inside the glaze layers and coloration of the decorations of the potsherds were also evaluated in the study. Furthermore, micro-Raman spectra provided bases for evaluation of firing temperature of the glazes based on the polymerization index (Ip) values. The low Ip values, for all of the analyzed samples (except for two of them), indicated that the glazes were rich in lead oxide and should have been fired at temperatures below 700 °C. In the Raman spectra of the glazes, several pigments and/or colored minerals were identified: These were namely lead white, anatase, quartz, calcite, red ocher, lazurite and carbon black.