a Politecnico di Milano Dipartimento Chimica Materiali e Ingegneria Chimica “Giulio Natta” , Milan, Italy
b Università degli Studi di Milano, Dipartimento di Chimica, Milan, Italy
c Getty Conservation Institute, LA, USA
Email: lucia.toniolo@polimi.it
Keywords: Raphael’s cartoon, monitoring, particulate matter, lining system
In the occasion of the conservation work and new installation of one of the masterpieces of the Veneranda Biblioteca Ambrosiana collection - the “School of Athens” by Raffaello Sanzio, dated 1508, 1:1 preparatory cartoon for the wall-painting in the Vatican rooms - two important aspects for the exhibition were investigated: the microclimatic condition of the exhibition room with particular regard to the determination of the concentration of fine particulate matter (PTS, PM10, PM2,5 and PM1), and the new lining system adopted for the vertical framing of the cartoon in the new showcase.
Actually, this diagnostic campaign, based on a strong collaboration with the team of the Ambrosiana’s curators[1] was carried out according to the specific conservation needs of this artwork: the knowledge of the situation of the exhibition room regarding the fine particulate matter was dramatically important to design the showcase and its air filtration solution, and a new lining system was deemed necessary for the new and safe installation of the cartoon inside the showcase.
Total suspended dust (PTS) was monitored during two different periods (fall and spring), in the exhibition room (n.5) and in the front room (n. 4) where the access to visitors was as usual for the museum. Specific fine dust fractions, PM10, PM2.5 and PM1, were analysed and compared with the data supplied by the outdoor monitoring units of the regional environmental agency (ARPA, Lombardia). Moreover, a chemical and morphological characterization of the particles was done to assess the possible risk level for the artifacts. The results of the fall campaign indicated that PTS concentrations was over the standard European limits and that the source is essentially from outdoor; PM10 concentration is, in the cold season, above the standard limit for the museum indoor environment.
For what concerns the study to select the material proposed as lining systems for the cartoon, the mechanical behaviour of four multi-layered paper and tissues composites was tested and discussed with the restorer1. Uniaxial tensile testing was used to characterize both the single layer materials and the overall mechanical behaviour of the composites. The testing protocol allowed to select together with the conservator, the most adequate composite material for the final lining of the cartoon, considering the stress value threshold for the framing, necessary for the new display situation.
References
Ioele, M., Sodo, A., Casanova Municchia, A., Ricci, M. A. and Russo, A. P. Chemical and spectroscopic investigation of the Raphael’s cartoon of the School of Athens from the Pinacoteca Ambrosiana., Applied Physics A 122.12 (2016): 1-15.
Gulotta, D., Villa T., and Toniolo L. Investigating the mechanical behaviour of the lining system for Raphael's Cartoon “The School of Athens”. Journal of Cultural Heritage 43 (2020): 1-11.
[1] The Authors are particularly grateful to Mons. Alberto Rocca and Dr. Elena Fontana of the Veneranda Biblioteca Ambrosiana in Milan, and to Dr. Elisabetta Giani of the Istituto Centrale del Restauro in Rome. Great thanks are also due for the fruitful collaboration with the Conservator Dr. Maurizio Michelozzi.