Non-destructive Analysis of Material Detachments from Polychromatically Glazed Terracotta Artwork by THz Time-of-Flight Spectroscopy
The damage caused by the environment to exposed glazed terracotta objects is usually not externally visible. For instance, the detachment of the glaze owing to subsurface crack formation or whole cavities in the area of the terracotta cannot be located visually. In this article, we demonstrate that terahertz time-of-flight spectroscopy is suitable to locate and measure the air gaps under the glaze detachments which could only be done by X-ray axial tomography before. This tool will be very useful to guide the restoration process, particularly for pieces that are still attached to buildings or other structures that cannot be transported to a tomography facility.
KeywordsTerahertz Non-destructive test Cultural heritage Terracotta Engobe Glaze
The authors would like to thank the Deutsche Bundesstiftung Umwelt (Germany) for their financial support and the Lower Saxony office for the protection of monuments and sites to provide us with the investigated object.
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