Reading the past: non-invasive infrared analysis of Herculaneum papyri

The papyri of Herculaneum, preserved by carbonization after the Vesuvius eruption occurred in 79 AD, are nowadays the focus of research interest, as they constitute an important challenge for both scientific and philological fields. Being a rare and invaluable source of information on ancient Greek philosophy and literature, reading the texts contained in papyri is fundamental. However, it is also highly challenging due to their heterogeneous morphology, varying degrees of carbonization, and state of preservation. The carbon-based ink used for writing is not visible to the naked eye and remains difficult to detect even with optical imaging techniques. This necessitates a multi-technique approach, careful optimization of experimental parameters, and rigorous statistical data analysis to enhance text readability and extraction. This contribution shows the results of a multi-technique approach carried out in the framework of the ERC Advanced Grant 885222-GreekSchools[1] by using NIR reflectography, hyperspectral SWIR imaging, high-resolution digital microscopy and pulsed thermography. The results enabled the characterisation of the papyrus morphology and the reading enhancement of several portions of the text in the investigated pieces.