How did Michelangelo paint the Sistine Chapel ceiling?

Michelangelo used fresco, applying water-ground pigment to freshly laid wet lime plaster. Because the plaster stays workable only for a few hours, the vault was painted in sections, each finished in a single day. He prepared the figures first as drawings and full-size cartoons, transferred the outlines to the plaster, and worked from a scaffold of his own design. [1] [2]

According to one account, Michelangelo built a wooden platform held up by brackets set into holes in the wall, designed to be moved across the chapel as work progressed. Methods.art, citing the biographers Condivi and Vasari, says he rejected Bramante's platform, which hung on ropes through holes pierced in the vault, and built one standing on props off the walls instead. The sources describe the support slightly differently, but agree he designed it himself. Because the scaffold had to be dismantled and moved as each new area began, the work advanced in stages. [2] [1] [3]

The surface was awkward as well. The ceiling is a barrel vault intersected by smaller vaults over the windows, so there are no flat surfaces except around the windows. [4]

Fresco allows no later correction, so the design came first. Methods.art describes chalk studies made from a live model, followed by a full-size cartoon. The outline was then pushed through onto the wet plaster. Far Out Magazine describes this as pouncing: holes were poked along the outlines and charcoal dusted through them, leaving paintable guidelines. It says Michelangelo's assistants helped prepare the cartoons, while Methods.art, following Vasari, says he sent away the Florentine fresco painters he had hired and finished the vault largely alone. [1] [3]

Only as much plaster was applied each morning as could be painted that day, and the unpainted edge was cut away at night. These daily sections are called giornate, and they remain visible today. As the lime cures it binds the color into the wall, which makes the paint durable but prevents revision. Michelangelo also scraped some of the wet plaster to suggest depth, leaving the visible outlines around figures that are considered characteristic of him. [2] [1]

The accounts differ on one point. Far Out Magazine reports that some art scholars think he went over details such as faces on dry plaster to strengthen the color. Methods.art, drawing on Vasari, notes that he wanted a dry finishing pass but never applied it, and that ultramarine, which will not hold in wet lime, was among the colors that never arrived. [3] [1]

Methods.art, relying on Vasari and Condivi, says he worked about twenty meters above the floor with his face turned upward. Condivi reports that afterward he could hardly see properly when looking down. Vasari records that the Roman lime mix bloomed with mold after the first third of the vault. The second half took twenty months and was uncovered on All Saints' Day 1512. The PBS piece adds that the method took considerable experimenting to get right, and that it is a reason the ceiling has lasted. [1] [5]