Material Insights into Giotto's Frescoes: A Comprehensive Study of Fragments from Saint Catherine Chapel

This thesis presents a detailed spectrochemical examination of the Giottesque frescoes, with a focus on fragments from the arch of the Saint Catherine Chapel in the Basilica of St. Anthony, Padua. These fragments were collected prior to the restoration intervention initiated in April 2021, as part of the UNESCO Padova Urbs Picta application. Throughout its history, the chapel experienced multiple restoration phases, significantly deteriorating frescoes believed to be the work of Giotto himself. The CIBA – Interdepartmental Research Center at the University of Padua conducted a diagnostic investigation to guide the restoration. They utilized surface mapping and material analysis techniques, including Fiber Optic Reflectance Spectroscopy (FORS) and Raman Spectroscopy, for in situ analysis of pigments. Additionally, microRaman stratigraphic examination was conducted on micro-samples. These preliminary analyses yielded valuable insights into pigments and mortars but left some certain key aspects underexplored, including organic compounds (likely binders or adhesives) and the precise composition of black residues. Furthermore, the identification of pigments in green and blue areas remained inconclusive. Building on the initial research, this thesis aims to expand our comprehension on these frescoes by utilizing advanced analytical techniques on nine specific fragments confirmed as original. Deeper insights into the materials, including pigments, binder, and dyes, were obtained through the use of confocal microscopy, Raman spectroscopy, SEM-EDS, and microFTIR. The comparison of these analyses was done with existing literature and other fresco cycles from Giotto, including his work at the Scrovegni Chapel. The results offer new evidence supporting the attribution of these frescoes to Giotto, as the materials and techniques observed align closely with those documented in his authenticated works. The use of comparable pigments in Giotto’s cycles offers fresh perspectives into his material selections and working methods. The comparison serves to strengthen the argument of attribution by demonstrating a similarity in the range of pigments used in both the Saint Catherine Chapel and Giotto’s other frescoes, including the Scrovegni Chapel. The research ultimately contributes to both the continual preservation of the chapel and the broader discourse on Giotto’s artistic legacy and his technical approach to fresco painting.