Mosaics: in art, surface decoration of small colored components--such as stone, mineral, glass, tile, or shell--closely set into an adhesive ground. The mosaic pieces, usually small squares, triangles, or other regular shapes (called tesserae), are applied to the surface, frequently a wall or floor, which has been prepared with mortar or adhesive to receive the design.
Mosaic differs from inlay in that the pieces are applied to the surface and not inset into a recess below the surface. Each mosaic piece is small, and it is only when the piece forms part of an overall mosaic design that it takes on decorative significance.
Mosaic as an art form has most in common with painting. It represents a design or image in two dimensions. It is also, like painting, a technique appropriate to large-scale surface decoration. Unlike the painter, however, the mosaic artist is limited in the range of colors available to him by the physical limitation of his materials. It is difficult, therefore, to achieve the same variation of light and shadow as is possible in painting, although mosaic has qualities that render it more effective for distance effects. The light-catching qualities of the glass tesserae used in Byzantine mosaic work, for example, as well as the elimination of the middle tones in Byzantine mosaics gave a greater brilliance than painting ever did. Like each decorative medium, mosaic has qualities unique to itself, which lends it particular suitability to certain decorative functions.
The earliest known mosaics date from the 8th century BC and are made of pebbles, a technique refined by Greek craftsmen in the 5th century. Pebbles of uniform size, ranging in color from white to black, were collected and used uncut to form floor and pavement mosaics. Even with this seemingly limited technique, Greek craftsmen were able to create elaborate and complex designs, using pebbles between one and two centimeters in diameter and outlining areas with tiny black pebbles. By the 4th century, pebbles painted red and green were added to give greater variety of effect.
Throughout antiquity, mosaic remained primarily a technique used for floors or pavements where durability and resistance to wear were paramount considerations. Stone, especially marble and limestone, was particularly suitable for this purpose. It could be cut into small pieces and the natural colors of stone provided a reasonable basic range of hues for the artist.
The use of glass for mosaic originated in the Hellenistic period, and it was to remain the most important mosaic material right through the Byzantine period. Glass could be made in any color, and thus the range of color available to the artist was virtually unlimited. Glass was less suitable than stone for floors, though its lightness made it particularly suitable for wall mosaic where durability was not so important. During the Early Christian period, gold and silver glass tesserae were invented, made by applying metallic foil to the glass. This "mirror glass" enabled even greater intensity of light to be created, and gold in particular was to create one of the most characteristic effects of the great shimmering mosaics of the Byzantine period. In the 6th century AD, Byzantine mosaicists were using a gold background as the norm. They also developed a technique of setting tesserae into the mortar at a sharp angle to reflect the maximum amount of light.
The Romans used mosaic widely, particularly for the floors of domestic buildings. Fine examples have survived from Pompeii, Herculaneum, and Ostia. During the Early Christian period, wall mosaics came into favour as church decoration, and these were to remain the major form of decorative art throughout the Byzantine period. The greatest examples of Byzantine mosaic work are at Ravenna at the churches of S. Apollinaire Nuovo and S. Vitale, where the continuous "skin" of rich mosaic is an integral part ofthe architecture. Striking later examples were executed at Torcello, near Venice, in the 12th century; at Daphni, near Athens, in the 11th century; and at St. Mark's cathedral, in Venice, from the 11th to the 14th century.
Last modified: Thurs Nov 19, 1998 / Jeremiah Genest