Fig. 5
From: Analysing the glaze of a medieval ceramic fragment from the Durres Amphitheater in Albania
Classification scheme for glazes. The scheme is based on the ratio of alkali content to lead content (as [24]), dividing the three fields of alkaline glaze, alkaline-lead glaze and lead glaze, and on the ratio PbO/SnO2. with divisor at 3.5, (following [23]), that represent a weighted average in the field of typically opacified glazes. The data used are from [26,27,28,29]. The dotted lines correspond to PbO/SnO2 from 20 to 2 for Ottoman, Timurids, and associated productions and between 3 and 6 for Iznik productions [30]