Spectrophotometric investigations at the museum: monitoring of colour changes during differentiated cleaning of the marble statues

The spectrophotometric investigations carried out during the cleaning treatments on the marble surface provide an useful support for choosing the best method to employ by monitoring, before and after the tests, both the chromatic coordinates and the spectral reflectance. Moreover, the colorimetric measurements allow us to evaluate the goodness of the chromatic level and the uniformity of the cleaned areas. The Laboratory of Physics and Indoor Environment of the Regional Center for Planning and Restoration has carried out the spectrophotometric investigations on the marble statues belonging to the Renaissance statuary collection of the Regional Gallery of Sicily Palazzo Abatellis in Palermo (Italy). The purpose of these analyses was to monitor the superficial colour changes during the cleaning treatments and after the restoration works. In particular, this paper reports the results obtained from the analyses made on: the famous “Busto di Gentildonna”, known as “Eleonora di Aragona” (by Francesco Laurana, XV century), the “Natività con cori di angeli” (by Palermo school, XV century) and the “Annunciazione” (by Antonello Gagini, XVI century).