Venetian plaster is a smooth and often shiny plaster design that appears textured but is smooth to the touch. It is one of the most popular and traditional of plaster decorations. It is a wall and ceiling finish consisting of plaster mixed with marble dust applied with a spatula or trowel in thin multiple layers which are then burnished to create a smooth surface with the illusion of depth and texture.
When applied correctly Venetian plaster can be used to create a highly polished, rock-hard, marble-like finish. Venetian plaster is especially useful on surfaces where marble panels could not be installed easily and on surfaces that would be too expensive to have carved from real marble such as columns, corbels and curved walls.
Venetian plaster can be tinted or colored using natural or synthetic colorants. The ability to tint Venetian plaster is especially helpful when a specific color of "marble" is desired, or when a color that does not exist naturally is wanted. When left un-burnished Venetian plaster has a matte finish that is rough and stone-like to the touch. Un-burnished Venetian plaster is also very brittle and damages rather easily. Techniques include marmorino, scagliola, and sgraffito.
Widely used in Italy its appeal has spread through North America but now worldwide. Because of the hours of workmanship involved pricing places it in the high-end market. However, many examples can be seen in public buildings, bars, restaurants, etc. Its waterproofing and anti-bacterial qualities as well as visual effects have also made it very desirable for luxury bathrooms and other wet areas. Not confined to interior use, it can be seen on the exterior of many buildings to great effect.
The material may be veined with colors and applied to a core or a desired pattern may be carved into a previously prepared scagliola matrix. The pattern’s indentations are then filled with the colored, plaster-like scagliola composite and then polished with flax oil for brightness followed by a coat of wax for protection.
The combination of materials and technique provides a complex texture and richness of color not available in natural veined marbles. A comparable material is terrazzo.