Micro-analytical study of a rare papier-mâché sculpture

The analysis of a Portuguese "papier-mâché" sculpture depicting Saint Anthony is presented in this case study. Several questions were addressed such as the characteristics of the support, pigments used, and artistic technique in order to establish a possible timeline for its production. Qualitative analyses of the cross-sections and of the paper support were performed by optical microscopy using reflected light. Two polychrome layers from different periods and a rag pulped support were identified on the sculpture. The use of micro X-ray fluorescence and Raman microscopy techniques enabled the differentiation of coloring materials used in both polychromies. Semi-quantitative analyses of the gilded samples were also performed by scanning electron microscopy in combination with energy-dispersive spectroscopy allowing the determination of a common Au-Ag-Cu alloy with differences in the purity of the gold. The identified coloring materials lead us to believe that the sculpture was produced in the 19th century, being overpainted in the first half of the 20th century.