Affresco e mezzofresco: studio sperimentale e procedure analitiche per la caratterizzazione delle tecniche pittoriche

The recognition of the painting technique adopted by an artist is often a matter of debate in studies for the characterization, restoration and conservation of mural paintings. Here we present the results of an experimental study and contribute to the definition of criteria and analytical procedures for the recognition of fresco and mezzo fresco painting techniques. Two sets of fifteen coloured strips were painted using different traditional pigments, including lime white, according to both the fresco and mezzo fresco painting techniques. These samples were then prepared in polished think sections and analysed by optical microscopy for micro-stratigraphy, by SEM for obtaining BSE images and elemental maps, and by FT-IR. The comparison of micro-stratigraphic sequences and distribution of chemical elements in each of the two sets of samples displayed systematic differences between the fresco and mezzo fresco painting techniques, independently on the pigment used, suggesting objective distinctive criteria and standardized operational procedures.