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Microanalyses and monitoring of the XVI century wall Paintings in the "Messer Filippo" cell of the tower of Spilamberto (MO), Italy

Cultural Heritage, Image, structure and Materials: conservation and restoration

University of Bologna Team Leader: Di Lonardo Gianfranco - Professor - Dep. of Physical and Inorganic Chemistry.

University of Bologna Research Group: Di Lonardo Gianfranco - Professor - Dep. of Physical and Inorganic Chemistry; Ospitali Francesca - Research Fellow - Dep. of Physical and Inorganic Chemistry.

Partner/Collaborations:

  • Dipartimento di Chimica Fisica e Inorganica, Università di Bologna;
  • Istituto di diagnostica e sperimentazione per il restauro dei beni culturali (IDBC), Pieve di Cento (BO);
  • Dipartimento di Chimica e Chimica Industriale, Università di Pisa;
  • Comune of Spilamberto (MO);
  • Soprintendenza per Patrimonio Storico, Artistico, Etnoantropologico di Modena e Reggio Emilia, REGEL (Torino)

Context and objectives

In the medieval tower of Spilamberto, near Modena (Italy), during the restoration works of 1946, a small cell was found. The four walls of the cell were entirely covered by monochrome reddish paintings and inscriptions, a sort of diary, work of a man imprisoned there in the first half of XVI century who wanted to leave a memory of a tragic history lived by him as actor or witness.
In the last sixty years the deterioration of painted surface largely increased, specially after the restoration of the tower in the ‘80s. In particular a whitish substance covered the surface of the paintings, making them almost disappear. Thus, a conservative-restorative project was need to preserve this particular historical-artistic document.

Methodologies and equipment

The project started with a scientific investigation of the employed materials and the painted technique, basic information to understand the causes of the deterioration and to plan the intervention.
UV and IR reflectography were carried out directly in situ. Then, micro-samples were collected from different panels, with different tone (from reddish to brownish hue), and they were studied by SEM-EDS, XRD, micro-Raman, micro-FTIR, GC-MS and Py/GC-MS techniques.
Moreover, a monitoring system has been installed in the cell and in the adjacent room to check the indoor microclimate and clarify the influence of the environmental agents, such as temperature (T), relative humidity (RH), and illumination, on the degradation process of the paintings.

Results

The multi-technique approach allowed to study the composition and the conservation state of the work. The paintings were obtained employing a red earth rich in iron (III) oxides (haematite, goethite and disordered goethite), with a considerable quantity of amorphous carbon particles. The pigment was applied directly on the plaster using a binder with both proteinaceous and ester components. Thus, one may infer that the painted technique was an egg tempera.
Concerning the whitish film that covers the pictorial coating, compromising the conservation state of the paintings and harming the readability of the work, micro-Raman demonstrated that this external layer is formed by micro-crystalline gypsum.
The identification of the employed materials and technique, supported by a microclimatic monitoring, enabled to advance a hypothesis about the causes and the mechanisms of degradation and, then, to plan a conservative action to safeguard this historical-artistic document.

Major details in:

  • F. Ospitali, A. Rattazzi, M.P. Colombini, A. Andreotti, and G. Di Lonardo, "XVI century wall Paintings in the "Messer Filippo" cell of the tower of Spilamberto: microanalyses and monitoring", Journal of Cultural Heritage, 2007, 8, 323-327