Active Thermography for Non‑invasive Inspection of Wall Painting: Novel Approach based on Thermal Recovery Maps

Abstract The development of novel non-invasive diagnostic methods to support artwork conservation is an important aspect for preserving human culture. For many years the restoration work has been assisted by various technologies with digital imaging systems playing an important role. An important request is the use of non-invasive diagnostic tools that allow the detection of defects and a comparison between their state before and after consolidation treatments. Among these, infrared thermography is a well-known non-invasive and contact-less imaging method that can enable low-cost in situ analysis. This work investigates the feasibility of an innovative active thermography approach based on the calculation of thermal recovery maps (TRMs) to detect detachments in wall painting. Its capabilities are tested on a work of art datable in the XVIII century by making measurements in situ before and after a consolidation work. The results achieved show how this analysis can significantly support the restoration works in the detection of critical/defective areas and for a pre-post restoration comparison of the artwork.