Plaster wall ornamentation in pompeii went right along with some of the earliest faux marble painting because plaster made a great surface to paint for artists because it would actually absorb part of the paint into the surface, fusing the color to the artwork. This was necessary before the advent of modern chemistry to have a long lasting fresco when tempura (or egg whites) and linseed oil where the primary substances used to bind pigments together. The reason the Sistine Chapel frescos and wall paintings still look astonishly beautiful after 500 yrs. is because they were painted on wet plaster by Michelangelo. At first when Michelangelo started painting, the ceiling of the Sistine Chapel, he made it so wet it started growing mold and had to be completely removed in favor of a better plaster formula developed by one of his art assistants. You'll find that problem solving goes hand in hand with the creation of a true artistic masterpiece. Sometimes technical challanges can be discouraging at first, but without them maybe we wouldn't have had the Sistine Chapel fresco.
People forget that before the bronze age was the plaster age. What do you think the insides of all of the ancient pyramids in South America and Egypt are carved out of? Plaster work is perhaps one of the most ancient arts. Plaster is even pre-pottery (meaning it pre-dates pottery) and helped lead to both the discovery of fired clay ceramics and the architectural advancement of human society anywhere plaster came into use.
THE PLASTER AGE
Humans have been working plaster for over 11,000 years. plaster was used in the interior walls of homes until drywall and sheetrock came into modern use. Now considered almost a dying art, plaster artists are a rare breed indeed. One of the things the old style of plastering walls provided was a layer of resistance against fire in a time when candles and oil lamps were the nightlite for thousands of years before electricity.