Restoration of the Sistine Chapel frescoes of the work. Based on this decision, according to Arguimbau's critical reading of the restoration data that has been provided, the chemists of the restoration team decided upon a solvent that would effectively strip the ceiling down to its paint-impregnated plaster. After treatment, only that which was painted "buon fresco" would remain. According to critics, the inherent problem with this approach is that it relied heavily upon an assumption that Michelangelo only painted "buon fresco", that he was always satisfied with the result at the end of the day, and that in four and a half years spent on the
Sistine Chapel ceiling "Life of Moses" on the left side. It was carried out by some of the most renowned Renaissance painters: Botticelli, Ghirlandaio, Perugino, Pinturicchio, Signorelli and Cosimo Rosselli. The upper level of the walls contains the windows, between which are painted pairs of illusionistic niches with representations of the first thirty-two popes. A draft by Matteo d'Amelia indicates that the ceiling was painted blue like that of the Arena Chapel and decorated with gold stars, possibly representing the zodiacal constellations. It is probable that, because the chapel was the site of regular meetings and Masses of an elite body of officials