Evolution of azulejo glaze technology in Portugal from the 16th to the onset of the 19th century

Azulejos have been applied to architectural settings in Portugal for the last five centuries and represent one of its most unique art forms. In this article a group of representative samples regarding the chronology and typology of the majolica azulejos produced by the Lisbon workshops from the second half of the 16th century (beginning of majolica azulejos production in Portugal) up to the first quarter of the 19th century (after which more indus-trialized manufacturing processes were introduced) are studied. SEM-EDS was used to obtain morphological and chemical information on the glazes, ceramic bodies, and their interfaces. The results show that a major shift from lead-rich to lead-alkali glazes occurred in the transition from the 16th to the 17th century, while from then to the end of the studied period the same basic technology prevailed. The Lisbon tiles production is also considered in the European context.