Cor e Técnica na Cerâmica de Revestimento Medieval: o Caso dos Ladrilhos Cistercienses do Mosteiro de Alcobaça

Abstract

Founded in 1153, the Monastery of Alcobaça reflects the original values of the Order of Cister through its elegant architecture. The glazed tiles that once coated the floor of the apse worked as a rare decorative element through the patterns created with their different colours and shapes. Considered 13th-century originals, these are some of the first examples of architectural glazed tiles in Portugal. The main goal of this research was to characterize their colour palette through a multi-analytical study of the glazes. The techniques used were optical microscopy (OM), particle-induced X-ray emission micro spectrometry (μ-PIXE), and electron scanning microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS). The colours identified in the glazed tiles, all monochromatic, were white, turquoise blue, brown and different shades of green. The analyses revealed that this palette was obtained with tin oxide, copper oxide and iron oxide in different amounts mixed with lead glazes. The identification of tin-opacified glazes suggests this being one of the first examples of this Islamic technology used in ceramic pavements in Christian Portugal.