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 ceiling to a strongly projecting painted cornice that runs right around the ceiling, separating the pictorial areas of the biblical scenes from the figures of Prophets, Sibyls, and Ancestors, who literally and figuratively support the narratives. Ten broad painted crossribs of travertine cross the ceiling and divide it into alternately wide and narrow pictorial spaces, a grid that gives all the figures their defined place. A great number of small figures are integrated with the painted architecture, their purpose apparently purely decorative. These include two faux marble "putti" below the cornice on each rib, each one a male and female pair;