The conservation state of parchments is typically assessed using invasive and sometimes destructive investigation techniques. Scientists from Université Paris-Saclay, the CNRS, École Polytechnique, and the French Ministry of Culture have developed a non-destructive and non-invasive advanced optical imaging technique to quantitatively assess the degradation state of parchments. The approach was validated using artificially-aged samples and then applied to 13th century parchment manuscripts from the renowned collection at the Chartres Library. Their work was published in the journalr parchemin datés du 13e siècle, issus du prestigieux fonds de la médiathèque de Chartres. Ces travaux ont fait l’objet d’une publication dans la revue Science Advances le 16 juillet 2021.