Michelangelo used buon fresco for most of the Sistine Chapel ceiling.
In buon fresco, an artist applies pigment mixed with water to fresh, wet plaster. The color becomes part of the wall as the plaster dries, creating a durable surface. Michelangelo and his assistants worked in sections called giornate, each representing the amount of plaster that could be completed in one day.
The technique required careful planning because corrections became difficult after the plaster dried. Michelangelo painted the ceiling between 1508 and 1512, working high above the chapel floor on specially designed scaffolding. The ceiling’s curved architecture made the project especially demanding.
Buon fresco is different from fresco secco, in which paint is applied to dry plaster. Some details may have been added or retouched dry, but the major painted composition depends on wet-plaster fresco. Restoration has helped distinguish original fresco work from later additions and deposits.