Thermographic analysis of bronze sculptures

Abstract

In this work we investigate various aspects of the finishing process in ancient bronze sculptures by means of active infrared thermography (IRT). Active IRT provides information on surface and sub-surface features of the investigated artefact, by analysing the heat diffusion process induced within the sample by appropriate thermal stimulations usually produced by absorption of light emitted by different sources. The aim of this research is, in particular, to investigate the processing of bronze surfaces, revealing repairs like plugs, fillings, local castings and concealed marks.

Combined use of infrared imaging techniques for the study of underlying features in the Santa Maria in Cosmedin altarpiece

“…IRT is one of the so-called photo-thermal techniques, based on the thermal analysis of samples heated by light absorption, that have been extensively used for the determination of different thermal parameters of different kind of materials (Marinelli et al 1995;Marinelli et al 1996;Zammit et al 1988Zammit et al , 2011Maldague 2001;Mercuri et al 2003;Gavrilov et al 2014;Paoloni et al 2016). Concerning cultural heritage investigations, IRT has been successfully used for the characterization of structural and the subsurface features in a large variety of artefacts (Daffara and Fontana 2011;Mercuri et al 2013aMercuri et al , 2013bMercuri et al , 2017aMercuri et al , 2017cMercuri et al , 2018aDoni et al 2014;Pucci et al 2015;Orazi et al 2016Orazi et al , 2019.…”

Pulsed Thermography Applied to the Study of Cultural Heritage

“…According to this method, after casting, the bronze requires the repairing of casting faults-like cavities, porosities, and openings-and the cold working process, a finishing step where several tools, such as chisels, burins, and files, are used [60,61]. Finally, the marks left by such tools are usually erased or concealed during the subsequent polishing of the surface and/or the patination [60].…”

“…Finally, the marks left by such tools are usually erased or concealed during the subsequent polishing of the surface and/or the patination [60]. However, these workings produce plastic deformations and inhomogeneities in the structure of the bronze and they can be identified by IRT [61], even after the final polishing.…”

Mid-wave Infrared Reflectography and Thermography for the Study of Ancient Books: A Review

“…Imaging techniques operating in the mid-wave infrared (MWIR) (3-5 μm) have been successfully used for investigations in the field of cultural heritage. Among others, infrared thermography (IRT) has proven to be a valid tool for the non-destructive inspection of artworks and to measure the constituting materials thermal parameters (Grinzato 2004;Ludwig and Rosina 2005;Avdelidis et al 2007;Blessey et al 2010;Gomez-Heras et al 2010;Bodnar et al 2012;Candoré et al 2012;Maev and Gavrilov 2013;Gavrilov, Maev, and Almond 2014;Di Tuccio et al 2015;Orazi et al 2016;Zhang et al 2017;Mercuri, Caruso et al 2018), like other photothermal techniques (Zammit et al 1988;Mercuri et al 2003;Mercuri et al 2008;Zammit et al 2011;Paoloni, Mercuri, and Zammit 2016). Moreover, IRT detects subsurface features in artworks and locates their position .…”