Introduction and Fun Facts

Investigation One: Discovering Perspective

Perspective. This word, in art as well as in life, holds several meanings and embraces several concepts. Investigations One, Two, and Three of the Science and Art CELL have been designed to help students explore the various concepts denoted by this word. In Investigation One, students will focus on perspective as it applies to the ability to visualize depth in our three-dimensional world and the ability to represent depth in a two-dimensional medium.

Students will begin their exploration by focusing on differences in what they see in their field of view when standing at different locations. As the Investigation continues, they will be asked to observe the appearance of parallel lines as the lines move away from them. In doing so, they will measure the width between the two lines at a point near and far from their eyes. As a result of their experiments, they will discover that part of our ability to perceive depth results from differences in the portion of the field of view that an object occupies. The same object when close to our eyes takes up a much larger portion of our field of view than when it is farther from our eyes. As a result, the image of the “distant object” that formed on the retina of the eye is proportionately smaller than the image of the “near object.” (see image above left of the Eiffel Tower).

Perception of Perception – The Eye and Brain

As we develop from infancy viewing near and far objects, our brain uses this information to formulate a pattern or rule that as objects retreat in the distance, they become smaller. The brain then utilizes this rule when viewing objects, allowing for a generalization of size. For example, we “know” that mountains in the distance are much larger than a house that is close to us. The mountains appear small because they are distant, yet the rule set up by the brain compensates because we know that as we would approach the mountains, they would become larger and larger.

Light reflected from an object enters the eye through a small hole called the pupil.  A lens then focuses the incoming image on the back of the eye on a screen filled with nerve cells called the retina. If you look at the illustration below carefully, you will notice that the image from the lens is upside down on the retina. The brain will later invert and correct this image. At this point, the nerve cells in the retina convert the incoming image into nerve signals that follow an optic nerve into the brain. Finally, our brain interprets the signals based on our previous experiences.

Artists and Perspective

In addition to investigating the mechanics behind depth perception, students will explore how artists learned over the course of history to translate this pattern of nerve signals and then images into something that can be illustrated in two dimensions (on paper) in order to create the appearance of depth or three dimensions. During their exploration, students will discuss the concept of a vanishing point and its perfection during the Renaissance.

As a part of the discussion, students will focus on the concept that parallel lines, in theory, will never meet. However, when parallel lines moving away from the viewer appear to unite at a single point in the distance, the point of intersection is called the vanishing point.

A vanishing point gives an object or image a sense of depth. When a vanishing point is used, objects will appear larger the closer they are to the viewer, and smaller the further they become from the viewer. When artists discovered how to add perspective to their work, through the use of vanishing point, art was transformed from a flat, unrealistic representation of the subject, to representations with depth, distance, and a more three-dimensional and realistic representation. The understanding and use of vanishing point coincided with the radical transformation in art that occurred with the Renaissance.

As a part of this Investigation, students will view paintings from before and after the Renaissance. Their discussion of the paintings will combine what they learned about the field of view and image formation in the eye with the use of vanishing point and manipulation of object size as a way to understand how depth is both perceived and represented.