What bokeh can tell us about art.

The study of bokeh tells us something vital and fascinating about art. In an article on bokeh, the author draws attention to the "cat's eye effect" where out of focus highlights appear as ovals with sharply converging corners (the shape of a cat's eye). The concept is illustrated with a photograph by Edo Engel of a street sign surrounded by what appears to be a whorl of cat's eye highlights. The author states "When there are many OOFH's [out of focus highlights] scattered across the frame, the cat's eye effect yields the impression of a rotational background motion." (http://www.vanwalree.com/optics/bokeh.html 2007)

What is fascinating about this, besides an interesting effect?

We learn from this phenomena the elongated shape of the disks implies movement. Any elongated shape implies motion, which automobile designers take great advantage of. This sense arises from how the human visual perceptual system interprets elongated forms. These forms, for some evolutionary psychological/perceptual reason, suggest movement.

The phenomena is used by the artist to create a meaningful statement, by understanding the effect the disks have on the human perceptual system, by known that human beings seeing the elongated disks will experience a sense of movement, that the sense of movement can be introduced into an otherwise static and flat scene. The sense of movement, further, can be used to evoke metaphor, as the photographer does by placing the sign for "Wildey" street in the center of motion, the name suggestive of "wildness."

This shows how an astute and observant artist can discover and use perceptual effects. To do so requires an approach to art that does not just involve knowledge of rational qualities and effects, but also irrational effects, which can give rise to apparently rational perceptions and ideas. It tells us that one cannot just "think" one's way to artistic success but must take into account perceptual and psychological effects, which are entirely irrational. It does not make any sense that out of focus ovals impart in the viewer a sense of motion, but nevertheless, they do.

In a second example, the author discovers color harmonies between the background out of focus highlights and foreground out of focus flowers. No viewer would ever think about this, but they do experience it perceptually, which sneaks into and influences our thoughts and feelings about the scene unconsciously.

It is the astute artist who looks for and discovers perceptual effects, which are frequently seen as defects, and employs them to produce meaningful art works.

There is a long history in music of categorizing sounds according to their "consonance" or "dissonance" with the former being pleasing and the latter unpleasant. However, the perception and aesthetic usefulness of consonant or dissonant sounds depends on their context. The same is true of bokeh. There is no good or bad bokeh, and I would hazard that "pleasant" and "unpleasant" is too limiting a range. The use of bokeh depends on the subject. I have seen extraordinarily beautiful photographs exhibiting the double line "nisen-bokeh" effect where the out of focus double bands echo the straight repetitive forms of conifer leaves.