Fresco

Fresco—the medium behind Michelangelo’s Sistine Chapel and Raphael’s _School of Athens_—is a wall-painting technique dating to antiquity. To create a fresco, artists apply a mixture of powdered pigments and water to wet lime plaster, prompting a chemical process that fuses the pigment with the wall. Because plaster dries quickly, artists must complete their frescos in sections, which are called giornata, Italian for “a day’s work.” While frescos were most popular during the Italian Renaissance (Italy’s hot, dry climate providing especially favorable conditions for their preservation), the medium was revived during the 20th century by Mexican Muralists like Diego Rivera.