Characterization of a wooden Brazilian sculpture using µXRF and µCT

The scientific characterization of historical pieces reflects the history of a people, as it brings countless information about the technology and cultural knowledge of a given civilization. These studies often involve a certain level of interdisciplinarity, as technology and history come together in the search for the characterization of a piece. In many cases it is possible to determine the period in which the artifact was created, identify the techniques used by the artist, provide data of a possible restoration process, in addition to helping to identify possible forgeries in valuable works. In this paper, two non-destructive characterization techniques were used: micro-X-ray fluorescence (µXRF) and X-ray microtomography (µCT), with the aim of characterizing a wooden Our Lady of the Immaculate Conception sculpture. µXRF measurements were carried out at 30 spots on the sculpture to identify the pigments used. It was possible to detect overlapping layers of paint, the presence of gold in some ornaments, and the use of pigments that have not been used since the 19th century, such as vermilion. The images generated by µCT were used to analyze the internal structure of the piece, its fixing points and the techniques used by the artist, in addition to enabling the observation of hollow. From the results obtained, it is concluded that two types of wood were used, the vermilion pigment applied in the mouth area is likely original, and the piece has probably undergone restoration.