Murals on plaster, also known as frescos, are a type of painting technique that involves applying pigments to wet plaster. This technique has been used since ancient times and is still used today to create beautiful works of art. Frescos are often found in churches, palaces, and other public buildings, and can be seen in many different styles and colors. The term fresco comes from the Italian word for fresh, referring to the fact that the paint is applied to wet plaster.