The Creators: A History of Heroes of the Imagination (72 page)

The principles of linear perspective were their rediscovery. The ancient Greeks used foreshortening in their vases of the fifth century
B.C.
, and Hellenistic painters created illusions of depth. Vitruvius himself defined scenography as “the shading of the front and the retreating sides, and the correspondence of all lines to the vanishing point, which is the center of a circle.” Agatharchus of Samos (fifth century
B.C.
), who painted a “scene” for a tragedy of Aeschylus about the time of the Peloponnesian War (and was then enlisted by Alcibiades to decorate his house), wrote a basic book on perspective. Followed by Democritus and Anaxagoras, he “showed how, given a center in a definite place, the lines should naturally correspond with due regard to the point of sight and the divergence of the visual rays, so that by this deception a faithful representation of the appearance of buildings might be given in painted scenery, and so that, though all is drawn on a vertical flat façade, some parts may seem to be withdrawing into the background, and others to be standing out in front.” Although in practice the ancients never mastered quite precisely the geometrically derived perspective of Brunelleschi and Alberti, late Hellenistic and Roman wall paintings from Pompeii and from a house on the Palatine show that they had mastered an illusionist technique and that it survived.

But somehow the mastery of perspective and the idea of a vanishing point disappeared in the Middle Ages in a rare example of the loss of a well-developed technique. Dominated as we are by graphic vistas in perspective, we hardly remember the philosophers’ arguments against this “perspective” way of seeing the world. Plato, who had his own way of looking at everything, objected to the very same “deception” of the senses that Vitruvius had praised as a way of giving a “faithful representation of the appearance of buildings in painted scenery.” If two objects or two persons were really the same size, Plato argued, the honest artist should make them so in his picture, and not depict one smaller than the other simply because it was seen at a greater distance. Deploring this reckless “innovative” spirit of the perspective painters, he praised Egyptian art for not using perspective. In Egypt, he noted, “no painter or artist is allowed to innovate … or to leave the traditional forms and invent new ones.” The result was that the traditional ways had survived unchanged for “ten thousand years … and no
exaggeration—their ancient paintings and sculptures are not a whit better or worse than the works of today.” Plotinus, too, praised the absolute honesty of Egyptian art, in which all objects were shown in their true proportions, not foreshortened to match the illusion of distance.

The reasons for the medieval loss of perspective are obscure, but their rediscovery is well documented and vivid. It was the work of no man of theory but of the practical and inventive Brunelleschi. His friendly first biographer Antonio Manetti (1423–1491), writing only a few years after Brunelleschi’s death, praised him as “either the re-discoverer or the inventor” of “what painters today call perspective, because it is part of that science which aims at setting down well and rationally the differences of size that men see in far and near objects, such as buildings, plains, mountains, and landscapes of all kinds and which assigns to figures and other things the right size that corresponds to the distance at which they are shown.” Manetti credited him with rules that artists had used ever since.

For his epochal experiment Brunelleschi used only a small wooden panel about fourteen inches square and a flat mirror of the same size. On the panel he had painted in perspective a picture of the baptistery that stood on the piazza opposite the cathedral of Florence, as seen from just inside the central door of the cathedral. The part representing the sky he covered with burnished silver to reflect the passing clouds. Into the painting Brunelleschi cut a small hole directly opposite the position of his eyes as he had stood inside the cathedral portal. The hole was small as a lentil on the painted side, but opened wider in the back so he could put his eye against it and look through.

The flat mirror that he needed for his experience—exactly the size of the painted panel—would only recently have become available. Elegant ladies in the Middle Ages carried on their belts portable round mirrors in ornamented cases of ivory and silver, and the mirror (
speculum
) was a favorite medieval metaphor. But only in the early thirteenth century was the technology developed for putting on glass a backing of silver or lead, which finally made possible large flat mirrors. Venetian glassmakers prospered by marketing these in the early fourteenth century.

Dante himself was fascinated by the divine geometry of light observed in mirrors. When he reached the Ninth Sphere of Paradise (the
Primum Mobile
), he turned from Beatrice to behold God as a nondimensional point of light ringed by nine glowing spheres of the angel hierarchy (in John Ciardi’s translation):

In Purgatory, dazzled by reflected sunlight, he noted God’s symmetry:

It was this mirror magic that centuries later would enchant the halls of Versailles.

With his small painted panel and his mirror Brunelleschi performed his epochal perspective experiment in the piazza of Florence on a day in 1425. Under the portal of the cathedral and facing the baptistery he held the unpainted side of the panel close against his face and peered through the hole. With his other hand he held the mirror at arm’s length facing inward toward the painting. “When one looked at it thus,” Manetti reported, “the burnished silver …, the perspective of the piazza, and the fixing of the point of vision made the scene absolutely real. I have had the painting in my hand and have seen it many times in those days, so I can testify to it.” Brunelleschi’s “point of vision” was the perspective “vanishing point.” He inspired others to design their paintings around a vanishing point, but Manetti insisted that none was Brunelleschi’s equal. Uccello (1397–1475), fascinated by the technique of perspective, enlisted the aid of the mathematical Toscanelli and applied it with great skill in the battle scene of
The Battle of San Romano
(now in the National Gallery in London), in the
Flood
in Santa Maria Novella in Florence, and numerous sketches. He was so engrossed by it that it was said he went on drawing perspective sketches and would not stop even for meals. Responding to his wife’s call, Uccello would exclaim, “What a sweet thing perspective is!” The joys of perspective did not wear off. Later Renaissance painters luxuriated in its delights.

Giotto and others before had found their own personal ways of capturing space. But now Brunelleschi had opened a public geometry of perspective.
Luckily his younger friend Leon Battista Alberti was the perfect complement to his mentor’s practical genius. What would have come of Brunelleschi’s experiment if there had not been close at hand a mathematically sophisticated artist with literary talent?

Luckily, too, Alberti was a man of broad culture, with a good classical education and knowledgeable in the long tradition of Western works on optics. The subject of light and how it reached the eye had fascinated scientists and philosophers, ancient and modern—which makes the medieval loss of the techniques of perspective all the more remarkable. Among its ancient exponents, besides Vitruvius (c.25
B.C.
), were Euclid (c.300
B.C.
), whose pioneer
Optica
aimed to define the rectilinear visual rays; Ptolemy, whose
Optica
(
A.D
. c.140) had applied Euclid’s insights to the laws of refraction, and whose
Geography
had projected the spherical form of the earth onto a two-dimensional map of the world; Galen (
A.D
. c.175), whose misleading physiology of the eye governed centuries; and, perhaps most important, the great Arab scientist Alhazen (
A.D.
c.1000), whose treatise offered a persuasive mechanistic theory of sight. More recently, Roger Bacon’s
Opus Majus
(c.1260) had provided an able compendium. An enterprising archbishop of Canterbury, John Pecham (c.1230–1292) had then composed his popular
Perspective Communis
(
A.D
. c.1270) which reconciled the ideas of his predecessors and would govern European optics through the Renaissance. What remained to be done was to focus all this miscellaneous learning on the needs of the artist.

This is precisely what Alberti’s
Della Pittura
(1436), dedicated to Brunelleschi, aimed to do. By defining the divine mathematics of perspective, he established the painter’s profession in the universe of humanist learning. Now art too would no longer be concerned with mere opinions, but with
certezze
(truths). The guidance that his Vitruvius would give to architects, this work now gave to painters. It was no simple revision of ancient texts, nor a mere recipe book, but the first work we know that relates the artist’s task to the laws of optics, and so raise the painter above the artisan. Now the practitioner of a liberal art, the painter became an artist.

The treatise of the thirty-five-year-old Alberti transformed the painter’s vision as well as his craft. From a decorative surface on which objects were displayed the painting now became a pictorial space containing objects. As Alberti explained how objects in the picture should be diminished in direct proportion to their distance from the viewer, his “artificial perspective” created a three-dimensional space on a two-dimensional surface. Painting for Alberti and followers became a science of space.

Earlier painters had begun with the furniture, Alberti began with the room. His perspective geometry declared the independence of space:

Alberti conceived his picture as the cross section of a visual pyramid. Its apex was in the eye and its base in the objects depicted, with its space extending through successive planes to the vanishing point, where all the planes (orthogonals) converged. A horizontal line through the vanishing (centric) point defined the horizon. As an aid he set up and looked through a
velo
, or reticulated net, which Dürer and others later used to help them grasp the artificial perspective. This mathematically homogeneous space gave a new unity and coherence to any painting.

Though these devices may seem obscure to the modern layman, they were plain enough to Alberti’s painter-contemporaries. They increasingly followed this prescription for defining the space that their painting encompassed. Just as Suger’s architecture at St.-Denis revealed the divine mystery of light to the faithful through the transparent walls, so Alberti’s perspective geometry of light-filled space revealed the divine symmetry of the visible world. The laws of optics, as the ascetic archbishop of Florence, Saint Antonio (1446–59) explained, showed God’s way of diffusing his grace (
lux gratiae
) through the universe. The science of perspective, by making painters into philosophers, had created an eighth liberal art. And as the interpreter of the divine order in the visible universe the artist acquired the dignity of the scientist. Toscanelli (1397–1482), the versatile Florentine cosmographer whose maps guided Columbus and whose sun dial adorned the cupola of the cathedral of Florence, called Brunelleschi “a new Saint Paul.” Exhilarated by the mathematics of space and light, Alberti himself thought the painter had become “almost another god”—a Narcissus seeing his own beauty reflected in nature.

The young Masaccio (1401–1428) was already startling the Florentine worshipers by his perspective illusion of a chapel seen through the wall of Santa Maria Novella. And Alberti’s mathematics stirred interest and enthusiasm for perspective. The unexcelled elegance and color of Domenico Veneziano’s disciple Piero della Francesca (c.1420–1492) tempt us to forget
his epochal contribution to the marriage of science and art. Late in life, Piero seems to have abandoned painting to write his own
De prospectiva pingendi
(
On Perspective in Painting
, c. 1474–82). Advancing Alberti’s techniques, he aimed to demonstrate the sovereign geometry of nature. The many aspects of nature, he wrote, were best grasped by the eye if they were expressed in simple geometrical forms. It is not surprising that twentieth-century cubists hailed him as their prophet. Centuries before them, he had anticipated Cézanne’s prescription that “within nature all forms are based on the cylinder, the sphere, the cone.” Yet Cézanne himself would pioneer a revision and a flattening of the painter’s pictorial space.