Non-destructive examination of panel paintings structures by Terahertz waves

Terahertz (THz) spectroscopy and imaging techniques have made progress in these 10 years, and some transportable systems have been applied to conduct non-destructive tests on various materials and objects. Since THz waves (or rays) can penetrate opaque materials and provide both material and structural information without contact, THZ techniques are expected to be useful in the investigation of cultural heritage objects. In this paper, we report examples of THZ application on the investigation of the preparations layers of some panel tempera paintings.