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
Illusionistic ceiling painting sotto in sù". This was the prototype of illusionistic ceiling painting that was to become an important element of Italian baroque. Correggio at Parma took the illusionistic ceiling a step farther in his frescoes of Christ and the Apostles for the cupola at the San Giovanni Evangelista and in the "Assumption of the Virgin" in the dome of the Cathedral of Parma, which is Correggio's most famous work (1520–24); in these frescos Correggio treats the entire surface as the vast and frameless vault of heaven in which the figures float. In a visual continuity between the architectural interior and its