Putting Things in Perspective
Renaissance art paid homage to its Greek and Roman ancestors, but at the same time forged its own path. It wasn't enough to copy the classics; Renaissance artists went one better. Different methods of artistic representation were developed during the fifteenth and sixteenth centuries, and Leonardo popularized several of them, establishing gold medal standards that future artists would emulate.
One of the most enduring innovations in Renaissance drawing was the notion of linear perspective. The concept of perspective involves the idea that it's possible to represent a three-dimensional shape (such as an apple or building) on a two-dimensional piece of paper or canvas. Sounds simple, but that's because we take it for granted today. Perspective can be called a “factual art,” rather than an “interpretive art” or one which doesn't aim to represent the world as it is actually seen.
Leon Battista Alberti (1404–1472) devised a mathematical model for drawing in perspective, where the artist pretended to draw as if through a window. This method made use of a “horizon line,” which represented eye-level, and used “vanishing points” that served as connection points for all lines of sight. These points helped to designate locations for all objects in the scene. Artists drew “visual rays” from vanishing points, and through these rays, they could create objects composed of right angles (such as walls, bricks, or anything else with a sharp edge). Early Renaissance architects such as Brunelleschi and Alberti worked with linear-perspective techniques, and Leonardo was a major proponent of this new drawing method.
One-point perspective is a particular type of perspective drawing, and one that's still taught to today's art students. This flavor of perspective is called “one-point” because, as the name suggests, it contains only one vanishing point. It is also sometimes called single-point perspective.
Single-point perspective is very useful for scenes that look down a narrow corridor or alley. Leonardo's The Last Supper is an excellent example of an interior scene that used this type of linear perspective. The vanishing point for this scene is right behind the face of Jesus; all lines (people, tables, wall niches) point in to Jesus, emphasizing his focus as the center of both the painting and the religious nature of the scene. As the eyes follow the slanting lines of the walls, they cannot help but fall upon the face of Jesus—and that is the purpose of using one-point perspective.
Two-point perspective is another method of drawing perspective. Rather than a single point, it uses two vanishing points along the horizon line. Since the vanishing points lie on the horizon line, it's possible to create perspective scenes that show the undersides of high objects, as well as the topsides of low objects. For this reason, artists tend to incorporate two-point perspective into landscapes and other scenes that contain wide angles of view. Two-point perspective is also used whenever the artist wants to highlight the corner of a building, hence its application in outdoor scenes.
Other, less-common types of perspective were developed in later years. Three-point perspective utilizes three sets of parallel lines where the third “dimension” points down, so that all objects appear to be spiraling into a downward vortex. Four-point perspective forces objects to appear fatter around the middle, and stretched out tall as they curve upward. Five-point perspective uses five vanishing points to basically create a circular image; this type of projection was used in church paintings, as well as other situations where it's desirable to show a full 180 degrees of content in a single image.
In learning how to construct precise, accurate perspective drawings, Leonardo may have worked with a device called a perspectograph. The idea behind it was similar to a mechanic's workbench, only it was for drawing. This system involved a table with a stand that had a cutout, through which the artist could trace perspective lines of objects beyond the stand. While Leonardo didn't invent the idea of drawing in perspective, he used it to such an extent that other artists soon came to admire, and then imitate, his style.