A mosaic is a piece of art or image made from the assemblage of small pieces of coloured glass, stone, or other materials. It is often used in decorative art or as interior decoration. Most mosaics are made of small, flat, roughly square, pieces of stone or glass of different colours, known as tesserae. Some, especially floor mosaics, are made of small rounded pieces of stone, and called "pebble mosaics".
Mosaics have a long history, starting in Mesopotamia in the 3rd millennium BC. Pebble mosaics were made in Greece mosaics with patterns and pictures became widespread in classical times, both in Ancient Greece and Ancient Rome.
Early Christian basilicas from the 4th century onwards were decorated with wall and ceiling mosaics.
Mosaic art flourished in the Byzantine Empire from the 6th to the 15th centuries; that tradition was adopted by the Norman Kingdom of Sicily in the 12th century, by the eastern-influenced Republic of Venice, and also in the Ukraine.
Mosaic fell out of fashion in the Renaissance, though artists like Raphael continued to practise the old technique. Roman and Byzantine influence led Jewish artists to decorate 5th and 6th century synagogues in the Middle East with floor mosaics.
Mosaic was widely used on religious buildings and palaces in early Islamic art, including Islam's first great religious building, the Dome of the Rock in Jerusalem, and the Umayyad Mosque in Damascus. Mosaic went out of fashion in the Islamic world after the 8th century.
Modern mosaics are made by professional artists, street artists, and as a popular craft. Many materials other than traditional stone and ceramic tesserae may be employed, including shells, glass and beads.
Two Main Methods
The direct method of mosaic construction involves directly placing (gluing) the individual tesserae onto the supporting surface. This method is well suited to surfaces that have a three-dimensional quality, such as vases. This was used for the historic European wall and ceiling mosaics, following underdrawings of the main outlines on the wall below, which are often revealed again when the mosaic falls away.
The direct method suits small projects that are transportable. Another advantage of the direct method is that the resulting mosaic is progressively visible, allowing for any adjustments to tile colour or placement.
The disadvantage of the direct method is that the artist must work directly at the chosen surface, which is often not practical for long periods of time, especially for large-scale projects. Also, it is difficult to control the evenness of the finished surface. This is of particular importance when creating a functional surface such as a floor or a table top.
A modern version of the direct method, sometimes called "double direct," is to work directly onto fiberglass mesh. The mosaic can then be constructed with the design visible on the surface and transported to its final location. Large work can be done in this way, with the mosaic being cut up for shipping and then reassembled for installation. It enables the artist to work in comfort in a studio rather than at the site of installation.
The indirect method of applying tesserae is often used for very large projects, projects with repetitive elements or for areas needing site specific shapes. Tiles are applied face-down to a backing paper using an adhesive, and later transferred onto walls, floors or craft projects. This method is most useful for extremely large projects as it gives the maker time to rework areas, allows the cementing of the tiles to the backing panel to be carried out quickly in one operation and helps ensure that the front surfaces of the mosaic tiles and mosaic pieces are flat and in the same plane on the front, even when using tiles and pieces of differing thicknesses. Mosaic murals, benches and tabletops are some of the items usually made using the indirect method, as it results in a smoother and more even surface.