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 three to get the width and by two to get the height. Maintaining the ratio, there were six windows down each side and two at either end. Defined proportions were a feature of Renaissance architecture and reflected the growing interest in the Classical heritage of Rome. The ceiling of the chapel is a flattened barrel vault springing from a course that encircles the walls at the level of the springing of the window arches. This barrel vault is cut transversely by smaller vaults over each window, which divide the barrel vault at its lowest level into a series of large