It was suggested that the interior of the 45 metre (147 ft) wide dome should be covered with a mosaic decoration to make the most of the available light coming through the circular windows of the drum and through the lantern. Brunelleschi had proposed the vault to glimmer with resplendent gold, but his death in 1446 put an end to this project, and the walls of the dome were whitewashed. Grand Duke Cosimo I de' Medici decided to have the dome painted with a representation of The Last Judgment. This enormous work, 3,600 metres² (38 750 ft²) of painted surface, was started in 1568 by Giorgio Vasari and Federico Zuccari and would last till 1579. The upper portion, near the lantern, representing The 24 Elders of Apoc. 4 was finished by Vasari before his death in 1574. Federico Zuccari and a number of collaborators, such as Domenico Cresti, finished the other portions: (from top to bottom) Choirs of Angels; Christ, Mary and Saints; Virtues, Gifts of the Holy Spirit and Beatitudes; and at the bottom of the cupola: Capital Sins and Hell. These frescoes are considered Zuccari's greatest work. But the quality of the work is uneven because of the input of different artists and the different techniques. Vasari had used true fresco, while Zuccari had painted in secco. During the restoration work, which ended in 1995, the entire pictorial cycle of The Last Judgment was photographed with specially designed equipment and all the information collected in a catalogue. All the restoration information along with reconstructed images of the frescos were stored and managed in the Thesaurus Florentinus computer system.