Summary

The key to illusionism has to do with the amount of processing you’re able to initiate. Since most processing occurs beneath the conscious level it’s very hard to see. The science shows you what the brain expects to do when something is experienced as real so you can do it even if you don’t see it at first, which will then sensitize your vision to better see it eventually.

Broadly we could say that illusionism is present in any art that triggers physiologic response in the way that reality does. Studying the science of perception and learning what has to be presented to the eye for it to be processed as real can be applied to drawing and painting so as to trigger more physical responses. One of the paradoxes of illusionism is that the skill itself is very intellectual, requires careful thought and attention, but the effects on the viewer are more preconscious and physical. It’s a tool for working directly with the viewer’s body and its mechanisms of response. In fact, the more unconscious processing you’re able to initiate the more real the image will seem.

Perception isn’t passive. It scans for what we need. It depends on and is most attuned to change. The stronger the change, the more intense the response. Where no change exists, these impulses don’t go to the brain. The boundary between one object and another is a big change. This is one of the first priorities is to find edges in order to separate objects from the surroundings. A sophisticated mechanism for finding real boundaries in the fluctuating light and movement of surrounding depends on microscopic movements of the eye called saccades. These little jerks move the retinal image back and forth reinforcing the real edges and giving rise to the phenomenon known as mach bands.

Mach bands refer to the intensification of the dark and light side of any edge to enhance the contrast.

Technically, to draw attention to something as mundane as paper itself, you must be very careful to create a uniform flow of changing tone. Any marks that show will undercut the sense of the surface of the paper itself. Two main steps are required to create a smooth gradation. First make the marks as small, light and close together as possible. One reason it’s important to keep them light is because you can always keep build ding up the tone, but once you’ve had to erase it’s harder to get control of the surface. The second step is to fill in all the holes, all the spaces between the marks trying to match the values. You can use your little finger to blend, but be gentle. Most of what makes strong illusion is done with the point of the pencil and careful attention and control. Holes average the tone.

Because you only have one pencil this week, experiment with using your little finger to smudge.

The illusion of paper has always had tremendous appeal for people who want to communicate on many levels. It’s a way of combining incongruous subjects without surrealism. It is popular with artists that want to communicate ideas or stories.

The eye doesn’t simply decode what’s out there. It has it’s own priorities about what is important and emphasizes those qualities. Our instincts are tuned to change. The stronger the change, the stronger the physical reaction. Where there’s no change the impulses don’t even go to the brain. Separating objects from surroundings is one of the priorities, finding edges. What makes an illusionistic edge depends on something called mach bands. This is the appearance of stronger dark on the darker side of the edge, and stronger light on the light side. This intensification of contrast reflects perception’s need to find boundaries, to separate objects. It’s the result of the way our eyes move as we look at the world. The image on the retina at the back of the eye is always moving so the eye evolved to depend on motion to see. Even if we think we’re holding still looking straight at something, our eyes are moving, delicate, fast, microscopic level jerks called saccades.