In situ and laboratory analysis on the polychromy of the Ghent Pantheon cork model by Antonio Chichi

Abstract

The Archaeological Collection of Ghent University Museum hosts one of the most remarkable cork models representing the Pantheon of Rome, made by the master Antonio Chichi (1743-1816). Ghent University started a restoration campaign dedicated to the cork masterpiece, which has great artistic value. Next to macroscopic analysis, an extensive physicochemical campaign was organised in order to study and document the composition and the preservation state of the polychromic layers of Chichi’s masterpiece. Portable and micro-Raman spectroscopy revealed the presence of materials such as carbon-based pigments, lead white, vermilion, chalk, gypsum, bassanite, Prussian blue and haematite on the exterior and interior of the cork model. A tin-containing layer was characterized on the exterior of the model. XRF instruments were employed to better understand the overall elemental composition of the model’s polychromic layers, positively identifying Pb, Sn, Zn, Ca, Hg, Fe at the exterior surface. Stratigraphic analysis was performed, with both analytical techniques, when possible. The detailed information provided by archaeology, art history and applied sciences on the cork model of the Pantheon, will help the conservators to better understand and restore the Pantheon model which will be exhibited in the new museum of Ghent University.