78. Roman Golden-Yellow Decorated Wall Plaster

Roman Wall Plaster

The term plaster indicates a mixture of slaked lime, a filler (usually sand) and water. The wall paintings at Pompeii are lime plaster preparations. The earliest plasters were lime-based. Around 7500 BC, the people of 'Ain Ghazal in Jordan used lime mixed with unheated crushed limestone to make plaster which was used for covering walls, floors, and hearths in their houses. Walls and floors were decorated with red, finger-painted patterns and designs. In early Egyptian tombs, walls were coated with lime and gypsum plaster and the finished surface was often painted or decorated. stucco was employed throughout the Roman Empire.

Plaster is made according to a long-known principle. The first application is with rough plaster with a filler of large grain size, and the following layers are successively finer. The last layer in Roman plastering was made of a mixture of lime and crushed marble, which was compacted to become shell-like and thereby watertight. Paint pigments dissolved in water or lime-water was applied on the still wet surface, al fresco, thereby integrating it with the top layer. Once the surface had dried, painting could continue a secco. The preparations could be complex and made in as many as seven layers as explained by Vitruvius. Considering these factors, plasters and wall paintings contain a lot of information regarding technology, craftsmanship, economy and tradition.