Portrait of an Etruscan Athletic Official: A Multi-Analytical Study of a Painted Terracotta Wall Panel

The Getty’s Etruscan painted terracotta wall panel, Athletic Official, recently has been speculated to be associated with a Caeretan wall panel depicting a Discobolus based on a shared iconography. To better understand the materials and techniques used to create the Getty panel and investigate its relation to extant Etruscan painted terracotta panels, a multi-analytical study was conducted, using broadband visible, IR, and UV imaging, along with scanning MA-XRF, FORS, Raman, SEM-EDS, and XRD analytical techniques. The analytical results together with PCA analysis suggest the clay support of the Getty panel is most similar in composition to that of panels from Cerveteri. A manganese black was identified in the decorative scheme; not commonly employed, this appears to be an important marker for the workshop practice in Cerveteri. Most significantly, the use of MA-XRF scanning allowed for invisible ruling lines on the Athletic Official, presumably laid down at the earliest stages of the creation of the panel, to be visualized. Taken together, the results of this study provide new insights into Caeretan workshop practice as well as provide a framework for better understanding the design and execution of Etruscan polychromy.

A Novel Technique for Full-Field Deformation and Temperature Measurement by Ultraviolet Imaging: Experimental Design and Preliminary Results

Synchronous measurement of full-field temperature and deformation at high temperature especially more than 1273 K is of much significance especially for part applications of turbine structures and materials. Non-contact optical methods attract more and more attention, however, current methods all face different challenges, such as strong light reflection on the surface of the specimen, disturbing radiation from environment, complex equipment setup, limited measured temperature not higher than 900 ℃ and so on. In this work, we develop an innovative technique to overcome some current problems. The measurement system employing an ultraviolet (UV) imaging system is composed of a scientific complementary metal oxide semiconductor (sCMOS) camera, a lens and a UV bandpass filter. The UV bandpass filter was used for thermal radiation elimination to acquire high quality images at elevated temperatures for deformation field calculation suitable for digital image correlation (DIC) method. The UV sensitive sCMOS camera without using active illumination was employed to collect enough UV radiation energy and eliminate the interference of the external ambient light, which is applicable for high accuracy temperature field measurement. Our system can realize the synchronous capture of image and temperature acquisition with passive UV imaging system at temperature not lower than 1473K. The feasibility of the method was verified through heating molybdenum (Mo) and Ni-based superalloy IC21 materials. The temperature fields of Mo measured by the established imaging system up to 1835 K with error less than 0.25% showed the effectiveness for temperature measurement. The estimated deformation and temperature field of Ni-based superalloy IC21 up to 1473 K with measured temperature error less than 0.5% demonstrated well the great potential of the UV imaging system in simultaneous measurement of temperature and deformation fields at elevated temperatures.

Characterization and Identification of Varnishes on Copper Alloys by Means of UV Imaging and FTIR

The application of varnishes on the surface of metal objects has been a very common practice since antiquity, both for protective and aesthetic purposes. One specific case concerns the use of tinted varnishes on copper alloys in order to mimic gilding. This practice, especially flourishing in the 19th century for scientific instruments, decorative objects, and liturgical items, results in large museum collections of varnished copper alloys that need to be preserved. One of the main challenges for conservators and restorers deals with the identification of the varnishes through non-invasive and affordable analytical techniques. We hereby present the experimental methodology developed in the framework of the LacCA and VERILOR projects at the Haute École ARC of Neuchâtel for the identification of gold varnishes on brass. After extensive documentary research and analytical campaigns on varnished museum objects, various historic shellac-based varnishes were created and applied by different methods on a range of brass substrates with different finishes. The samples were then characterized by UV imaging and infrared spectroscopy before and after artificial ageing. The comparative study of these two techniques was performed for different thicknesses of the same varnish and for different shellac grades in order to implement an identification methodology based on simple non-invasive examination and analytical tools, which are accessible to conservators.