Late middle age painting canvas of the our Lady of Rosary: a study of its materials and techniques

The altar cloth representing the Our Lady of Rosary, from the Santa Cruz Monastery, is in the Machado de Castro National Museum, in Coimbra (Portugal), and is a rare example of glue tempera painting on canvas from the late Middle Age. Despite these earlier paintings were common practice, in Portugal their investigation is scarce. This paper presents the study of this surviving medieval painting using a multi-analytical approach for the characterization of the techniques and materials applied. Observation under a digital handheld microscope revealed the original painting. Macro photography, ultra-violet fluorescence and infra-red photography were carried out. Micro-samples were analysed by optical microscopy and SEM-EDX, along with fibre identification of the support. The data obtained brought to light new evidences that gives an important contribution for the knowledge and study of these earlier paintings.