DAVID BY ANDREA DEL VERROCCHIO
The bronze statue was made between 1468 and 1969 by Verrocchio for Piero de ‘Medici, father of Lorenzo the Magnificent and Giuliano, who in 1476 sold the statue to the Signoria of Florence, who intended to display it in the Palazzo Vecchio, at the entrance to the Sala dei Gigli, as a hero symbol of the republican libertas. The work is currently displayed at the Bargello Museum in Florence.
THE PROBLEMS OF RESTORATION
The David, like other Renaissance works, had undergone over the centuries a series of surface treatments that had altered its original appearance. In particular, a patination had been applied and then renewed several times, above the gilding wanted by Verrocchio: these interventions had given the work a nearly uniform dark tone perhaps to adapt it to the taste of the time. From accurate diagnostic investigations, carried out in collaboration with the National Council of Research (CNR) of Florence, the presence of extensive gold leaf gilding covered with thick layers that completely concealed it was demonstrated.
Any solvent for organic components would have attacked the gold leaf and in any case, even assuming a bland chemical action, the manual finishing of surfaces with traces of gold leaf appeared impossible. The solution was identified in laser cleaning, in particular in the use of an Nd: YAG laser with optimized pulse duration of about 50s. The emission parameters were optimized so that the pressure and temperature gradient transferred to the gilding were kept low. The high reflectivity of the gold leaf at the wavelength used greatly contributed to the selectivity of the process. The surface was wetted during irradiation to keep the thermal peak low.
Client: Bargello National Museum – Opificio delle Pietre Dure – Florence
Restorers: Maria Ludovica Nicolai, Simone Porcinai
– B. Paolozzi Strozzi e M.G. Vaccari a cura di, David del Verrocchio. Un capolavoro dopo il restauro, Giunti Ed., 2004B.
– B. Paolozzi Strozzi e M.G. Vaccari a cura di, Il bronzo e l’oro. Il David del Verrocchio restaurato, Museo Nazionale del Bargello, Giunti Ed., 2003.