The surfaces of wood, stone, and plaster sculpture can be decorated with gold, silver, and other metals that are applied in leaf or powder form over a suitable priming. Metals, especially bronze, were often fire-gilded; that is, treated with an amalgam of gold and mercury that was heated to drive off the mercury. The panels of the Gates of Paradise in Florence, by the 15th-century sculptor Lorenzo Ghiberti, are a well-known example of gilded bronze.
Isaac, Jacob, and Esau, gilded bronze relief panel from the east doors (Gates of Paradise) of the baptistery in Florence, by Lorenzo Ghiberti, 1425–52. 79.4 cm square.SCALA/Art Resource, New York
Patination
Patinas on metals are caused by the corrosive action of chemicals. Sculpture that is exposed to different kinds of atmosphere or buried in soil or immersed in seawater for some time acquires a patina that can be extremely attractive. Similar effects can be achieved artificially by applying various chemicals to the metal surface, which is often heated to create a bond. This is a particularly effective treatment for bronze, which can be given a wide variety of attractive green, brown, blue, and black patinas. Iron is sometimes allowed to rust until it acquires a satisfactory colour, and then the process is arrested by lacquering. Electroplating
The surfaces of metal sculpture or of specially prepared nonmetal sculpture can be coated with such metals as chrome, silver, gold, copper, and nickel by the familiar industrial process of electroplating. The related technique of anodizing can be used to prevent the corrosion of aluminum sculpture and to dye its surface. Other finishes
The surfaces of metal sculpture can be decorated by means of numerous metalsmithing techniques—etching, engraving, metal inlaying, enameling, and so on. Pottery sculpture can be decorated with coloured slips, oxides, and enamels; glazed with a variety of shiny or mat glazes; and brought to a dull polish by burnishing.
Other materials have often been added to the surface of sculpture. The eyes of ancient figure sculpture, for example, were sometimes inlaid with stones. Occasionally—as in Mexican mosaic work—the whole surface of a sculpture is inlaid with mother-of-pearl, turquoise, coral, and many other substances. Forms, subject matter, imagery, and symbolism of sculpture
A great deal of sculpture is designed to be placed in public squares, gardens, parks, and similar open places or in interior positions where it is isolated in space and can be viewed from all directions. Other sculpture is carved in relief and is viewed only from the front and sides. Sculpture in the round
The opportunities for free spatial design that such freestanding sculpture presents are not always fully exploited. The work may be designed, like many Archaic sculptures, to be viewed from only one or two fixed positions, or it may in effect be little more than a four-sided relief that hardly changes the three-dimensional form of the block at all. Sixteenth-century Mannerist sculptors, on the other hand, made a special point of exploiting the all-around visibility of freestanding sculpture. Giambologna’s Rape of the Sabines, for example, compels the viewer to walk all around it in order to grasp its spatial design. It has no principal views; its forms move around the central axis of the composition, and their serpentine movement unfolds itself gradually as the spectator moves around to follow them. Much of the sculpture of Henry Moore and other 20th-century sculptors is not concerned with movement of this kind, nor is it designed to be viewed from any fixed positions. Rather, it is a freely designed structure of multidirectional forms that is opened up, pierced, and extended in space in such a way that the viewer is made aware of its all-around design largely by seeing through the sculpture. The majority of constructed sculptures are disposed in space with complete freedom and invite viewing from all directions. In many instances the spectator can actually walk under and through them.
kneeling VirginKneeling Virgin, willow, paint, and gilding, attributed to Paolo Aquilanoca, southern Italy, c. 1474–1500; in the Metropolitan Museum of Art, New York City.Photograph by KaDeWeGirl. The Metropolitan Museum of Art, New York City, The Cloisters Collection, 1925 (25.120.217)
The way in which a freestanding sculpture makes contact with the ground or with its base is a matter of considerable importance. A reclining figure, for example, may in effect be a horizontal relief. It may blend with the ground plane and appear to be rooted in the ground like an outcrop of rock. Other sculptures, including some reclining figures, may be designed in such a way that they seem to rest on the ground and to be independent of their base. Others are supported in space above the ground. The most completely freestanding sculptures are those that have no base and may be picked up, turned in the hands, and literally viewed all around like a netsuke (a small toggle of wood, ivory, or metal used to fasten a small pouch or purse to a kimono sash). Of course, a large sculpture cannot actually be picked up in this way, but it can be designed so as to invite the viewer to think of it as a detached, independent object that has no fixed base and is designed all around.
Sculpture designed to stand against a wall or similar background or in a niche may be in the round and freestanding in the sense that it is not attached to its background like a relief; but it does not have the spatial independence of completely freestanding sculpture, and it is not designed to be viewed all around. It must be designed so that its formal structure and the nature and meaning of its subject matter can be clearly apprehended from a limited range of frontal views. The forms of the sculpture, therefore, are usually spread out mainly in a lateral direction rather than in depth. Greek pedimental sculpture illustrates this approach superbly: the composition is spread out in a plane perpendicular to the viewer’s line of sight and is made completely intelligible from the front. Seventeenth-century Baroque sculptors, especially Bernini, adopted a rather different approach. Though some favoured a coherent frontal viewpoint, however active, Bernini is known to have conceived a work (the Apollo and Daphne) in which the narrative unfolded in details discovered as the viewer walked around the work, beginning from the rear.
The frontal composition of wall and niche sculpture does not necessarily imply any lack of three-dimensionality in the forms themselves; it is only the arrangement of the forms that is limited. Classical pedimental sculpture, Indian temple sculpture such as that at Khajuraho, Gothic niche sculpture, and Michelangelo’s Medici tomb figures are all designed to be placed against a background, but their forms are conceived with a complete fullness of volume. Relief sculpture
Relief sculpture is a complex art form that combines many features of the two-dimensional pictorial arts and the three-dimensional sculptural arts. On the one hand, a relief, like a picture, is dependent on a supporting surface, and its composition must be extended in a plane in order to be visible. On the other hand, its three-dimensional properties are not merely represented pictorially but are in some degree actual, like those of fully developed sculpture.
The Reign of JupiterThe Reign of Jupiter, marble bas-relief depicting Jupiter (centre) and Mercury (left), dating to the northern French Renaissance, c. 1550–70; in the Metropolitan Museum of Art, New York City.The Metropolitan Museum of Art, New York; Purchase, The Annenberg Foundation Gift, 1997, 1997.23, www.metmuseum.org
Among the various types of relief are some that approach very closely the condition of the pictorial arts. The reliefs of Donatello, Ghiberti, and other early Renaissance artists make full use of perspective, which is a pictorial method of representing three-dimensional spatial relationships realistically on a two-dimensional surface. Egyptian and most pre-Columbian American low reliefs are also extremely pictorial but in a different way. Using a system of graphic conventions, they translate the three-dimensional world into a two-dimensional one. The relief image is essentially one of plane surfaces and could not possibly exist in three dimensions. Its only sculptural aspects are its slight degree of actual projection from a surface and its frequently subtle surface modeling.