Perspective

   Technique used by sculptors and painters to create the illusion of three-dimensional reality in an image executed on a two-dimensional surface. Ancient painters had attempted with consider-able success to achieve this illusion, but in late antiquity the new Byzantine style, for reasons of taste rather than lack of skill, created a pictorial art that deliberately transformed paintings into a pattern ap-plied to an unabashedly flat, two-dimensional surface. In late me-dieval Western art, interest in the illusion of three-dimensional depth reappeared. The paintings of Giotto succeeded in creating an appear-ance of depth by a composition based on the placement of the figures in relation to each other and to the viewer; his technique did not, how-ever, extend the illusion beyond the foreground of the painting.

   Although interest in three-dimensionality is evident in later 14th-century painters, only at the beginning of the 15th century did artists discover and refine rules that guaranteed success in creating the illu-sion. Among the painters of the Flemish school, especially the broth-ers Jan and Hubert van Eyck, artists learned to suggest depth and three-dimensionality by careful variation of color and shading, a vi-sual trick known as aerial perspective, but they never worked out a set of rules that could be applied by less skilled artists. Almost at the same moment, Italian sculptors and painters were moving toward an alternative technique known as single-point or vanishing-point per-spective. In this system, the illusion is created by basing the compo-sition on a set of (invisible) converging lines that come together at a single point in the background, so that each object in the image is scaled appropriately in order to create the illusion that it is not set onto the flat surface of the work but is placed within the apparently three-dimensional world of the work of art. Unlike the Flemish aer-ial perspective, single-point perspective can be reduced to a set of mathematical rules that any competent artist can master.

   Although a biographer of the Florentine artist Filippo Brunelleschi about 1480 described two panel paintings made by Brunelleschi about 1413 that applied single-point perspective to create three-dimensional space, the earliest surviving work that demonstrates use of the new technique is the relief sculpture The Feast of Herod, created about 1425 by Donatello. About a decade later, the sculptor Lorenzo Ghiberti, in designing the 10 panels of his second set of doors for the Florentine Baptistery, applied the principles of single-point perspective with an ease and assurance that demonstrates full mastery of the new tech-nique. The panel depicting The Story of Jacob and Esau is a striking example of this success. In painting, shortly after Donatello's Feast of Herod, the painter Masaccio produced several works that showed a ma-ture ability to create three-dimensional appearance by applying single-point perspective in a variety of different configurations, represented by his Holy Trinity and The Tribute Money. Art historians conjecture that Brunelleschi, though he functioned primarily as an architect, was the actual discoverer of the rules on which single-point perspective was based, deriving his new method from careful measurement of exam-ples of ancient architecture and sculpture.

   The principles discovered by Brunelleschi and applied successfully by Donatello and Masaccio were codified by Leon Battista Alberti in his treatise Della pittura (ca. 1435-1436), which reduced the new tech-nique to a set of geometric principles that any artist could learn and ap-ply. Later Italian artists such as Piero della Francesca and Andrea Mantegna demonstrate increasing sophistication in use of the tech-nique. Mantegna successfully solved the problem of projecting a three-dimensional image onto a vaulted surface. Late in the 15th century, Italian painters also became aware of the type of aerial perspective de-veloped by the Flemish painters and began to combine it with their single-point method. This development is evident in the work of Leonardo da Vinci, whose paintings employ a delicate gradation of light and shading known as sfumato to enhance the illusion of a three-dimensional image. There is considerable evidence that some artists simplified their task by applying the principle of the camera obscura to project images onto the surface of their intended work.