Pigeons bob their heads up and down to gain depth perception. This deliberate movement of the head or body to achieve different views is known as motion parallax. By analyzing multiple viewpoints, the animal is able to determine the relative proximity of objects in space. Because our eyes produce overlapping views, humans can perceive depth without moving. Comparing the subtle differences between the left and right eye views, our brains produce a complex, three-dimension rendering of the world before us. This is known as stereopsis, and provides depth perception without head bobbing. Still, motion parallax plays a critical role in human perception as well.
As a teenager, I raced small sailboats on Midwestern lakes. On the upwind leg of a sailboat race, when boats can be some distance apart, it is often difficult to determine who is moving faster. A mentor once taught me the phrase “making trees”, sailing slang for going faster than your competitor. When you watch the shoreline beyond your competition and your competitor’s boat appears to be slipping relative to the trees (i.e. more and more trees appear in front of their boat), you are “making trees”, and this is good, because it means you are going faster. This is an example of motion parallax, which is also good, because without it we would have a hard time determining relative velocity.
This installation exploits another form of motion parallax, an auto-animating print known as the parallax panoramagram. Developed in the early 1900’s, the image consists of two parts: a barrier layer with a repeating pattern of thin, opaque lines, and an image layer containing a sequence of images broken up into vertical strips. As the viewer moves in relation to the piece, the change in perspective displays different sections of the printed layer, creating the illusion of movement.
I designed Parallax specifically for WindowWorks at Artpace. Because the gallery opens up to Main Avenue and is typically viewed from a car, bicycle or on foot, I wanted to activate the motion of the viewer in a meaningful way. Though the panels themselves are static, the movement of the viewer initiates a dynamic, animated effect. I am interested in this interplay between the audience and art object. Without movement, the work is static. With movement, time and space are activated to create a more complex engagement. Like the bobbing pigeon head, multiple perspectives must be witnessed to achieve the complete experience.
-Stuart Allen
