Le vetrate
The decorated windows in Michelangelo’s Library with all their references to contemporary pictorial art are a true masterpiece of glass craftmanship. Originally the windows were thirty, fifteen on each side of the Reading room in order to illuminate the two series of wooden benches or plutei. Today only twenty-seven windows survive in their ‘original’ condition; two windows are ‘blind’ and one has gone lost because in 1841 in order to build the D’Elci Rotunda the original disposition of the room was modified. The refined multicolour decoration was realized using grisaille and yellow silver techniques and probably following four recurrent patterns. The windows bear Medici heraldic devices – emblems, arms, winged putti - which can be referred to Clement VII and Cosimo I. A large number of windows bear the year in which they were reallized (1558, 1567, 1568 up until 1695). Although Michelangelo designed the architectural structure of the whole Library, after his departure from Florence (1534) the decorations and the windows were realized by other artists. In the past the windows have been ascribed to Giovanni da Udine; recent studies instead suggest that they were realized by Flemish artisans folowing models by Wouter Crabeth, also known as Gualtieri d’Anversa.
The windows have been restored many times in the past. The restoration works began in 2003 we made necessary because of the worsening of the conservation situation. In many parts the windows were not able to prevent rain entering and this could have caused damage to the gutters and floors. On the whole the windows were very fragile, both in their structure and decoration showing a general lack of colour particularly on the right side (exposed to the North) as well as numerous breaks, recent as well as old, the latter having been repaired with lead.
The restoration foresees the following phases:
1) Research of documentation into the history and previous restoration
2) Decision on the state of degradation of the building
3) Realization of a mobile scaffold
4) A map of the state of conservation
5) Diagnostic inquiry into the execution and composition
6) Microclimatic inquiry
7) Restoration of the window taken as a sample by l’Opificio delle Pietre Dure (Florence)
8) Planning and realization of special external double windows for protection
9) Cleaning and restoration of the intrados (lower or interior curve of arch) and architectural frames
10) Entrusting the remaining windows to private firms for restoration
11) Recuperation of blind windows via retro-illumination