Final answer:
Fresco paintings are always painted on plaster. It is an ancient technique of painting on wet plaster that becomes permanent when it dries. Buon fresco is a more durable mural painting technique.
Step-by-step explanation:
Fresco paintings are always painted on plaster. Fresco painting is an ancient technique of troweling wet lime plaster on a wall or ceiling and painting the wet plaster with a scene. When the plaster dries, the painting becomes permanent and will last until the plaster is damaged. Buon fresco is a more durable mural painting technique where alkaline resistant pigments are applied to wet plaster, allowing the pigment to chemically bond with the plaster.