ELI5: What Is Fresco Painting?

Fresco painting is a way of making art where you paint directly onto wet wall plaster so the picture becomes a permanent part of the wall itself as it dries.

Imagine you are baking a pizza:

• If you place pepperoni on top of the pizza after it comes out of the oven, it just sits there and can easily fall off. That is like regular painting on a dry wall.
• But if you press the pepperoni into the soft, wet dough before you bake it, the cheese and crust melt around it, locking it inside forever. That is fresco painting.

To make a fresco, an artist has to work like a baker with a timer:

• First, they spread fresh, wet plaster (a paste made of lime and sand) over a small section of a wall.
• Next, they quickly paint their picture using water mixed with colorful powder called pigment.
• As the wet wall dries and breathes in the air, a chemical reaction happens. The colors sink deep inside the plaster, turning the paint and the wall into the exact same piece of solid rock.