cristina giannini

Pubblicato in occasione del Convegno Internazionale di Studi " Giovanni Secco Suardo (1798-1873). La cultura del restauro tra tutela e conservazione dell’opera d’arte" (Bergamo, 9-11 marzo 1995).
Il convegno si è proposto come un’occasione di studio e di approfondimento dell’attività e degli scritti di Giovanni Secco Suardo (1798-1873) che nei decenni precedenti e successivi alla formazione dello Stato unitario in Italia, con spirito innovativo e lucida consapevolezza, svolse un ruolo di primissimo piano nel dibattito apertosi in Europa tra storici dell’arte, direttori dei musei, “conoisseurs”, collezionisti e restauratori sui temi cruciali della tutela, della conservazione e del restauro delle opere d’arte.

ABSTRACT Since the fifteenth century, in the Italian art, roof tiles, terracotta and, more generally, brick materials were adopted as artistic support for mobile paintings, curiously exploiting materials and techniques of mural painting. The small size and the low cost of these materials, jointly with easy availability as construction elements left over from building works, presumably favoured their use by artists for (self-)portraits, sacred and mythological representations. Both the application of pigments onto moist plasters following the typical procedure of fresco technique and the execution of details, even the entire depicted subject, by means of secco techniques, seem to testify a strict relationship with the coeval mural painting, as suggested by the evidence that the artists who experienced this type of mobile painting were also expert fresco painters (e.g., Andrea del Sarto, Pontormo, Giovanni da San Giovanni, Il Volterrano). The significant number of painted tiles preserved in the Florentine museums, dated back to the first two decades of the 16th century and mainly attributed to Bartolommeo di Paolo del Fattorino, known as Fra Bartolommeo (1472? - 1517), encouraged a specific multidisciplinary study, to figure out how such an interesting artistic production developed and if it actually constituted a workshop practice diffuse in the Renaissance Florence. To achieve this purpose, technical and scientific examination was carried out on the entire corpus of paintings on tile by Fra Bartolommeo, in the framework of co-operation with the Director and technical staff of the Museum of San Marco, Florence, where these paintings are permanently exhibited. In addition to the various style that seems to distinguish these artworks in different groups, nowadays attributed to distinct periods of the painter, the variety of the methods used to apply the plaster layers onto the brick support, the typology of the tiles and the technical features of the paint layers induce to rethink the classification of these paintings, starting from a more correct terminology for the description of the supports and a more precise identification of the manufacturing techniques. The documentary evidence about the provenance of all these tiles from the Convent of Santa Maria Maddalena in Pian di Mugnone (an hospice belonging to the Dominican Order of San Marco located just few metres from the north entrance to Florence) opened to promising results. Here a tile painted by Fra Bartolommeo, representing an Ecce Homo, is still inserted within the wall surface of a corridor at the ground floor, providing a reliable proof that the tiles were formerly wall embedded, as recorded by an archival document (1736). The results of the ongoing research on the artistic and building materials of the convent and its surroundings, undertaken in co-operation with Biblioteca Medicea Laurenziana, are shedding new lights on the manufacturing techniques of painting on tile in 15-16th century, whose fortune continued until the Baroque period, as it was appreciated by the Medici family itself to create architectural decorations.

Tecniche, metodi e principi del restauro, uniti a un repertorio completamente aggiornato della diagnostica applicata alla conservazione dei Beni Culturali, tecniche dell'arte, materiali, metodi e procedimenti esecutivi, sono raccolti in un volume di oltre 2.500 voci. L'opera prende in esame tecniche e materiali impiegati nella loro storia, strumenti e ricette del mestiere, durabilità e degrado dei manufatti artistici, per fornire le basi necessarie alla comprensione dei metodi di conservazione preventiva e di restauro. La parte relativa alla diagnostica e alla tecnologia dei materiali è particolarmente ampia per rendere conto dei recenti progressi. Tradotti in lemmi chiari e schematici, ma sempre esaustivi, vi si trovano i risultati degli studi degli ultimi dieci anni, elaborati da un'équipe di storici dell'arte e di scienziati.

This paper explores the added value of micro-chemical and microscopic approaches to gather scientific evidence that can technically explain the pictorial quality of an egg-tempera painting, and underpin assessments that otherwise would be based on naked eye observations only. Demonstration is here provided via the interdisciplinary investigation of the original technique used by Giovanni del Biondo in the polyptych Annunciation and Saints (1385 ca), Galleria dell'Accademia, Florence, Italy. The exquisite surface appearance makes this panel painting remarkable compared to artworks by coeval artists. Imaging techniques (UV, IR and IR false color), non-invasive single spot techniques (XRF and FORS spectrometry) and analytical investigations on eight selected micro-samples (ATR-FTIR, GC/MS and Py/GC–MS, ESEM-EDS) were combined to retrieve the palette and identify organic binding media and a superficial coating layer. Stratigraphic and micro-chemical data confirmed the use of a relatively simple egg-tempera technique applied on a ground made of gypsum mixed with animal glue, without complex stratigraphic superimposition of preparation and pictorial layers. Various pigments were identified, among which is the precious lapis lazuli. While Py/GC–MS highlight that the coating is made of dammar resin and honey mixed with animal glue, the results allow us to state that the painting was not intentionally varnished by Giovanni del Biondo. These outcomes shed a new light on the technical knowledge of this polyptych, and prove how challenging is the attempt to categorize egg-tempera recipes used by ancient painters at the turn of the 14th century.