Artists use perspective to represent three-dimensional objects on a two-dimensional surface (a piece of paper or canvas) in a way that looks natural and realistic. Perspective can create an illusion of space and depth on a flat surface (or the picture plane).
Perspective most commonly refers to linear perspective, the optical illusion using converging lines and vanishing points that makes objects appear smaller the farther away from the viewer they go. Aerial or atmospheric perspective gives things in the distance a lighter value and cooler hue than things in the foreground. Foreshortening, yet another type of perspective, makes something recede into the distance by compressing or shortening the length of the object.
The rules of perspective applied in Western art developed during the Renaissance in Florence, Italy, in the early 1400s. Prior to this time paintings were stylized and symbolic rather than realistic representations of life. For example, the size of a person in a painting might indicate their importance and status relative to other figures, rather than their proximity to the viewer, and individual colors carried significance and meaning beyond their actual hue.
Linear perspective uses a geometric system consisting of a horizon line at eye level, vanishing points, and lines that converge toward the vanishing points called orthogonal lines to recreate the illusion of space and distance on a two-dimensional surface. Renaissance artist Filippo Brunelleschi is widely credited with the discovery of linear perspective.
Three basic types of perspective -- one-point, two-point, and three-point -- refer to the number of vanishing points used to create the perspective illusion. Two-point perspective is the most commonly used.
One-point perspective consists of a single vanishing point and recreates the view when one side of the subject, such as a building, sits parallel to the picture plane (imagine looking through a window).
Two-point perspective uses one vanishing point on either side of the subject, such as a painting in which the corner of a building faces the viewer.
Three-point perspective works for a subject viewed from above or below. Three vanishing points depict the effects of perspective occurring in three directions.
Aerial or atmospheric perspective can be demonstrated by a mountain range in which the mountains in the distance appear lighter in value and a bit cooler, or bluer, in hue. Because of the increased layers of atmosphere between the viewer and objects in the distance, objects that are farther away also appear to have softer edges and fewer details. Artists replicate this optical phenomenon on paper or canvas to create the sense of distance in a painting.
Most experienced artists can draw and paint perspective intuitively. They do not need to draw the horizon lines, vanishing points, and orthogonal lines.
Betty Edward's classic book, "Drawing on the Right Side of the Brain," teaches artists how to draw and paint perspective from observation. By tracing what you see in the real world onto a clear viewfinder about 8"x10" held parallel to your eyes (the picture plane), and then transferring that drawing onto a white sheet of paper, you can accurately draw what you see, thereby creating the illusion of three-dimensional space.