From Bridget Riley’s painting you gain a definite, if useless, amount of information about the optical components and reciprocal effects of colors in various combinations and patterns. These combinations and patterns might be considered Riley’s invention; they obviously result from persistent research on her part.

In Shih-Li, wavy horizontal lines cause the surface to undulate in a series of diagonal ripples. Furthermore, with time the interwoven colors of the lines create a checkerboard of white and yellow light along these diagonals. Paean, the largest painting in the exhibition, is more rigid in structure and more devastating in effect. In it, tripartite vertical bands combining red, blue, and green in various sequences (always one color flanked on each side by another) cause the surface to disintegrate into a shimmering, almost blinding, light and the eyes to water. At this point, the vertical lines break up into pulsating little squares, like an animated version of Broadway Boogie Woogie.

A painting titled Veld has quite a different optical effect. It lacks the undulations of Shih-Li or the shimmering shake of Paean. The optical illusion doesn’t mount to climax in quite the same way; in fact, it almost seems to work in reverse. At first the painting simply looks like a series of green diagonal bands, each with an alternately white or yellow center. Closer examination reveals that all the centers are white but that each is alternately edged with hairline stripes of lavender or orange. Veld is relatively inert, like a number of other smaller works. When Riley’s paintings don’t do anything, they just sit there. Her patterns, on their own, are simply tacky, like fabric. They don’t exist for themselves; they succeed only when they obliterate themselves. The process of this obliteration can be startling. Riley has made such a minute and scientific study of one aspect of painting, the optics of color, as to remove it from the context of painting, either as a pictorial or a human experience. Her work is “nonreferential” in the truest sense. Despite the intelligence and acuteness of observation which Riley must employ to come up with these schemes, their appeal is to the eye alone—not as it is “a part of the mind,” but as it is just another muscle.

—Roberta Smith