Infrared and Terahertz Imaging for the Analysis of a Fresco Sample

Emma Vannini, Ilaria Catapano, Alice Dal Fovo, Valentina Di Sarno, Alessandra Rocco, Pasquale Maddaloni, Raffaella Fontana

Abstract

The stratigraphy of mural paintings comprises multiple plaster layers with varying thicknesses, each prepared with progressively finer sand. Due to this complex structure, wall paintings are susceptible to deterioration at different depths. Detecting subsurface and internal defects, as well as hidden features, is crucial in conservation to reveal underlying details and assess the artwork's condition. Infrared (IR) and terahertz (THz) radiation can penetrate beneath the surface, providing valuable diagnostic insights. In this work, a multi-technique survey was performed on a purpose-built sample using Near-Infrared (NIR) reflectography, active thermography in both Mid-Wave (MWIR) and Long-Wave Infrared (LWIR) ranges, and Terahertz Time-Domain Imaging (THz-TDI). The results demonstrate the capabilities and limits of these techniques in identifying subsurface features and highlight their complementary roles in the analysis and conservation of wall paintings.

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IMEKO-Metroarchaeo-2025-007.pdf

DOI

10.21014/tc26-2025.007

IMEKO TC

TC26 - Metrology for Cultural Heritage

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