# Pulsed Thermography Applied to the Study of Cultural Heritage
## 3 Results
### Analysis of Bronzes
#### 3.1.1 Repairs and Decorative Elements  
After the casting and the removal of the internal core material, the bronze sculpture can present openings made in order to insert the scaffolding elements necessary to support the mould inserted during the casting, which is then removed. These openings can be mended by different methods, the main ones referred to as mechanical and metallurgical repairs [48; 62]. Mechanical repairs consist of regular patches, wedged into undercut holes, which are commonly planned and well executed. Differently, metallurgic repairs are made by forming a clay mould over the missing area and then filling it first with wax and, then, with bronze in the so called _casting on_ method [62]. In the case of the Capitoline She Wolf, both mechanical and metallurgic repairs have been identified by means of the pulsed IRT and are sketched in Figure 3A. Concerning the mechanical repairs, for instance, the patch shown by the thermogram of Figure 3B had been made in order to fill the hole left after the removal of one of the scaffolding bars on which the sculpture is moulded [60]. As the area behind the patch is empty, a regularly shaped cavity with a depth smaller than the bronze wall thickness was applied around the hole, in order to host the patch. Then, the patch was mechanically forced into the cavity to cover the hole. Thermogram 3B shows a brighter (hotter) rectangle in the areas of the patch near its edges, which corresponds to the presence of a thermal barrier to the local heat propagation from the surface, while the central part, probably thicker, appears darker (cooler). Such thermographic features are consistent with a poor thermal contact between the patch edge and the underlying cavity support, where the bronze thus cools less rapidly than its surroundings. On the other hand, the patch of the right front paw, shown by the thermogram in Figure 3C, has been made in a metallurgic way. In this case, the local casting has given rise to an irregular patch, where the local casting material bonds with the gap contour areas. The lighter areas near the patch edges in the thermogram (Figure 3C) are due to the non-ideal thermal contact with the underlying gap edges. Such features also reveal the thinner nature of the edges of the patch, which becomes progressively thicker when moving toward its central area. The thermograms of Figure 3B,C have been obtained with the front face heating induced by using two flash lamps at their maximum power (3 kW each). It is worth noting that for this kind of analysis, the use of more lamps (three and four) has also been tested without obtaining a significant improvement in the quality of the thermograms, while making the illumination arrangement much more difficult for such in situ investigations. Figure 3: (**A**) Sketch of the positions of the mechanical and metallurgic repairs on the [PERSON] statue; thermograms of the mechanical patch on the shoulder (**B**) and of the cast-on patch on the right front paw (**C**) [48]. Decorative Elements  
IRT can also be used to investigate bronze decorative elements. For instance, it has been applied to the analysis of the She Wolf fur [47] in order to obtain information on its manufacturing process. The thermogram of Figure 4B, obtained with the front face heating produced by two flash lamps operating at 3 kW, reveals a series of inhomogeneities at the fur edges, circled by the dotted lines. These inhomogeneities could be generated during the casting process and in particular during the moulding of the wax model. In fact, each fur element is obtained from a serial model whose wax print was presumably applied directly on the wax model of the She Wolf body [47]. For this reason, the ihnomogenities at the fur edges could be associated with infiltration of the material used to make the external cloak in possible gaps left between the superimposed fur and the body wax models.