Nondestructive Evaluation of Lined Paintings by THz Pulsed Time-Domain Imaging

For the past 20 years, THz pulsed time-domain imaging has been used to study the internal structure of various paintings. The main advantage of this technique is that it can nondestructively provide depth profiles, as well as conditions of preparation and support layers, which are important in conservation planning. We have applied THz pulsed time-domain imaging to artworks with linings, which are additional layers of fabric or paper adhered to the back of an original painted work on canvas or paper to reinforce it, usually for conservation purposes. If the lining material or the interface between the lining and the original canvas or paper deteriorates over time, there is a risk of further problems. Therefore, THz pulsed time-domain imaging is expected to be suitable for examining lined paintings. In this paper, the investigation of artworks with lining layers using the THz pulsed time-domain imaging technique is presented, in addition to previous studies of Japanese panel screens and modern oil-canvas paintings with wax-resin linings, as well as a detached fresco painting mounted on a canvas by the "strappo" technique.