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
Restoration of the Sistine Chapel frescoes watercolour, to integrate the pictorial material. These areas are distinctively textured with vertical brushstrokes, not visible from a distance but easily discernible as restoration work when viewed close up. Certain small areas were left unrestored, in order to maintain a physical record of the previous restorations that had taken place, for example, an area left with overpainting and candle wax, and another area demonstrating the attempt to counteract salination with oil. Once the many layers of candle wax, varnish, and animal glue were removed from the surface of the Sistine Chapel frescoes, they became subject to dangers that could not