An integrated analytical approach for the characterization of repainted wooden statues dated to the fifteenth century

The present study aims to set-up an investigation integrated methodology to identify pigments and binders present in the original layers and the subsequent repainted layers that characterize two polychrome wooden statues dated to the fifteenth century. In particular a multi-analytical approach has been applied on two Ligurian Christs, the first one from San Bartolomeo parish in Zuccarello, the second from Borghetto San Niccolò (placed in Liguria region, Noethern Italy) both repainted many times during the centuries. By comparing the results of XRF analysis performed with portable instrumentation on the surfaces and on the stratigraphic sequences coming from different areas of the works of art, with the data obtained by SEM-EDS and corroborated with μ-FTIR and portable Raman spectroscopy findings, the pigments present in the different layers were identified. By μ-FTIR spectroscopy and thanks to the application of some staining tests (with Oil red and Amido black) the chemical nature of the organic binders employed was disclosed. Thanks to the presence of specific pigments, such as Prussian blue, barium sulphate, titanium oxide and some organic colorants, linked to specific historical periods, it was possible to date the layers and to reconstruct the history of the two examined statues. These detailed investigations on complex stratigraphic cross sections have been carried out as part of a conservation project and the results obtained have provided restorers with important information useful for the intervention on these statues and for their conservation.