A French term from the Italian basso-relievo ("low relief"), bas-relief (pronounced bah ree·leef) is a sculpture technique in which figures and/or other design elements are just barely more prominent than the (overall flat) background. Bas-relief is only one form of relief sculpture; figures created in high relief appear to be more than halfway raised from their background. Intaglio is another form of relief sculpture in which the sculpture is actually carved into material such as clay or stone.
Bas-relief is a technique as old as humankind's artistic explorations and is closely related to high relief. Some of the earliest known bas-reliefs are on the walls of caves. Petroglyphs were treated with color, as well, which helped to accentuate the reliefs.
Later, bas-reliefs were added to the surfaces of stone buildings constructed by ancient Egyptians and Assyrians. Relief sculptures can also be found in ancient Greek and Roman sculpture; a famous example is the Parthenon frieze featuring relief sculptures of Poseidon, Apollo, and Artemis. Major works of bas-relief were created around the world; important examples include the temple at Angkor Wat in Thailand, the Elgin Marbles, and images of the elephant, horse, bull, and lion at the Lion Capital of Asoka in India.
During the Middle Ages, relief sculpture was popular in churches, with some of the most remarkable examples decorating Romanesque churches in Europe. By the time of the Renaissance, artists were experimenting with combining high and low relief. By sculpting foreground figures in high relief and backgrounds in bas-relief, artists like Donatello were able to suggest perspective. Desiderio da Settignano and Mino da Fiesole executed bas-reliefs in materials such as terracotta and marble, while Michaelangelo created higher-relief works in stone.
During the 19th century, bas-relief sculpture was used to create dramatic works such as the sculpture on the Parisian Arc de Triomphe. Later, in the 20th century, reliefs were created by abstract artists.
American relief sculptors drew inspiration from Italian works. During the first half of the 19th century, Americans began creating relief works on federal government buildings. Perhaps the best known American bas-relief sculptor was Erastus Dow Palmer, from Albany, New York. Palmer had been trained as a cameo-cutter, and later created a great many relief sculptures of people and landscapes.
Bas-relief is created either by carving away material (wood, stone, ivory, jade, etc.) or adding material to the top of an otherwise smooth surface (say, strips of clay to stone).
As an example, in the photo, you can see one of Lorenzo Ghiberti's (Italian, 1378-1455) panels from the East Doors (commonly known as the "Gates of Paradise," thanks to a quote attributed to Michelangelo) of the Baptistery of San Giovanni. Florence, Italy. To create the bas-relief Creation of Adam and Eve, ca. 1435, Ghiberti first carved his design on a thick sheet of wax. He then fitted this with a covering of wet plaster that, once it had dried and the original wax had been melted out, made a fireproof mold into which liquid alloy was poured to recreate his bas-relief sculpture in bronze.