Renaissance perspective

The story

Paintings without depth

If you look at a painting from the Middle Ages, for example an altarpiece from the 13th century, you will notice some strange things. The figures look flat, as if they had been cut out. The background is often gold, with no landscape. The sizes do not follow reality: the Virgin Mary is bigger than the saints beside her, because she is more important, and buildings are smaller than the people walking into them. Medieval painters were not trying to copy what the eye sees, but to show the spiritual order of the world.

Things began to change with Giotto, around 1300, who made his figures more solid and placed his characters in rooms or landscapes with some depth. But there was still no rule for showing space accurately. It was in Florence, at the start of the 15th century, that a group of artists and scholars found one.

Brunelleschi's experiment

Filippo Brunelleschi was a Florentine goldsmith and architect, passionate about mathematics and geometry. Around 1415–1420, according to his biographers, he carried out an experiment, almost a conjuring trick. He painted a view of the Baptistery of Florence, the eight-sided building in front of the Cathedral, on a small panel with a hole in the middle. Then he stood just inside the central doorway of the Cathedral, a few metres from where he had painted, and looked through the hole from behind the panel, with the painted side facing the Baptistery. In front of the panel he held a mirror, which reflected the painting. When he took the mirror away he saw the real Baptistery, and when he put it back he saw the painting, and there was no difference: the painting was so faithful that it looked like reality.

The secret was “linear perspective”: a geometric method for drawing objects the way an eye placed at one exact point sees them. Parallel lines that move away from you, like the edges of a road or the beams of a ceiling, seem to come together at a single faraway point, the “vanishing point”, which lies on the horizon line; and objects become smaller as they move away, following a precise rule.

From practice to theory

The idea spread quickly. The young Masaccio was the first to use it in a spectacular way in the “Trinity”, a fresco painted around 1425–28 in Santa Maria Novella, in Florence: a chapel with a barrel vault seems to open up in the wall, so real that visitors stood there open-mouthed. Donatello used perspective in his carved reliefs, Lorenzo Ghiberti in the doors of the Baptistery, and Paolo Uccello in the “Battle of San Romano”, full of lances and foreshortened horses.

In 1435–36 a humanist and architect, Leon Battista Alberti, wrote the first treatise on painting, “De pictura” (“On Painting”), dedicating the Italian version to Brunelleschi and explaining how to build painted space: imagine the picture, he said, as an “open window” through which you look at the world. Later Piero della Francesca, a painter and mathematician, wrote a treatise on the subject, “De prospectiva pingendi” (“On Perspective for Painting”), and Leonardo da Vinci and Raphael brought perspective to perfection, with works such as the “Last Supper” and the “School of Athens”.

The word “perspective” comes from the Latin “perspicere”, which means “to see through”: it recalls Alberti's window. Artists learned the technique with grids of threads and measuring tools, and they often drew the geometric plan first, with the lines coming together, and only afterwards added the colours.

A revolution in the way of looking

Perspective was not only a technique. By placing the eye of the viewer at the centre, it reflected the new way of thinking of humanism, in which man is the measure of the world. The world became something that could be measured, calculated and shown with mathematics.