Infrared thermography analyses in the early Christian basilica complex in Cimitile (Italy)

This study explores the application of infrared thermography (IRT) in both mid-wave (MWIR) and long-wave (LWIR) infrared spectral ranges to assess the conservation state of architectural and decorative elements within the Early Christian Basilica complex of Cimitile (Italy). Dating back to the 3rd century AD, the complex includes multiple interconnected basilicas, floor mosaics, wall paintings, and burial structures, and is considered one of the most important Paleochristian archaeological sites in southern Italy. Over time, environmental factors and structural aging have led to widespread deterioration of its surfaces and materials. As a non-invasive diagnostic technique, IRT offers valuable insights into subsurface anomalies such as detachments, cracks, and moisture accumulation, making it an effective tool for preliminary assessment and long-term monitoring of cultural heritage structures. Passive thermography was used to analyse internal and external wall structures, while active thermography in the MWIR range was applied to wall paintings and mosaics. Comparative analysis between MWIR and LWIR imaging highlighted their respective advantages. The results revealed critical structural issues, including areas with compromised adhesion and significant moisture infiltration, both of which threaten the preservation of surface decorations and substrates. The integration of passive and active thermographic approaches enabled a multi-scale and multi-phenomenon diagnostic framework, offering comprehensive data to support restoration planning.