Sistine Chapel ceiling how the work progressed. It was customary for fresco painters to use a full-sized detailed drawing, a "cartoon", to transfer a design onto a plaster surface—many frescoes show little holes made with a stiletto, outlining the figures. Here Michelangelo broke with convention; once confident the "intonaco" had been well applied, he drew directly onto the ceiling. His energetic sweeping outlines can be seen scraped into some of the surfaces, while on others a grid is evident, indicating that he enlarged directly onto the ceiling from a small drawing. Michelangelo painted onto the damp plaster using a wash technique to apply
Sistine Chapel exterior can be seen only from nearby windows and light-wells in the palace. Subsidence and cracking of masonry such as must also have affected the Cappella Maggiore has necessitated the building of very large buttresses to brace the exterior walls. The accretion of other buildings has further altered the exterior appearance of the Chapel. The building is divided into three stories of which the lowest is a very tall basement level with several utilitarian windows and a doorway giving onto the exterior court. Internally, the basement is robustly vaulted to support the chapel. Above is the main space, the Sistine