Spectroscopic characterization of historical building materials: The case study of the Biblioteca Nazionale Marciana (Venice, Italy)

The building designed by Sansovino in 1532 as the new Mint of Venice underwent a change in its intended use, becoming in 1900 the Biblioteca Nazionale Marciana. A spectroscopic study concerning the surface stone materials of the current reading room (previously a courtyard) was attempted since the transformation lead to heavy micro- and macroclimatic variations. Many alterations were observed, such as blackening, cracking, incrustations, and mortars powdering. The employed techniques, such as Raman and Fourier Transform InfraRed-Attenuated Total Reflectance spectroscopy, allowed identifying the substrate main components and their alteration phases, mainly sulfates and nitrates. These data represent important information when approaching such a famous building because every further intervention must be based on accurate scientific results.