Movements in Art: From Rosso to Riley

Vision unifies the part of art and science that is of interest to the majority of readers of Perception. Artists are not always inclined to further the union. In this issue there are articles on works by two artists who have taken divergent views of the bond. On the one hand, David Melcher and Francesca Bacci provide an account of Medardo Rosso who strived to capture the features of the fleeting glance in his sculptures. On the other, Johannes Zanker, Melanie Doyle, and Robin Walker dissect some observational aspects of Bridget Riley's op art works. Riley, who is renowned for her scorn of optical analyses of her work (see Kudielka 1999), has had a major retrospective exhibition of her work on display at the Tate Britain in London (June ^ September 2003). The articles on both Rosso and Riley are concerned with the influence of eye movements (or their absence) on the effects their art produces. Both articles present interpretations of the respective artists from visual perspectives that differ markedly from those framed by art critics. Some years ago, the geneticist C H Waddington wrote a book entitled Behind Appearance in which he cast an analytical eye over developments in painting from Picasso to Pollock. The title was apt because he delved into the sources for nonrepresentational art, and he classified artists as either magicians or geometricisers. Bridget Riley was placed, of course, in the geometrical camp, and one of her illustrations reproduced by Waddington was Fall of 1963. Waddington remarked: `̀ The element of intellectual, and still more of visual, paradox, is a powerful influence in one of the most recent types of paintingöOp Art'' (1969, page 214). The allure of Fall does not pall; it is the principal subject of Zanker et al's article. Bridget Riley was born in London in 1931, and is best known for her high-contrast, black-and-white paintings of geometrically periodic patterns. More recently she has produced designs in colour. The works that have captured the imagination of visual scientists are those in black-and-white. Movements and distortions of the patterns are seen even though none are occurring on the picture plane. The dynamic changes are a consequence of processes within the visual system of the observer, and so they are truly interactive paintings. Riley came to international prominence when her work was shown in The Responsive Eye exhibition, held at the Museum of Modern Art, New York, in 1965. Her portrait in figure 1 is embedded in a drawn design that displays many of the visual distortions seen in her black-and-white paintings and prints, including Fall. The wavy radiating lines appear to shimmer and move, particularly around the inflection points of the curves; the contours fluctuate in clarity, being sharply defined at one moment and blurred at the next. It is when the contours are blurred that Bridget Riley's portrait can be seen. The phenomena manipulated by Riley and other op artists have long been known in visual science, but scientists have not exploited them with the ëlan of op artists. This reflects a fundamental difference in approach between science and art, even when dealing with the same phenomena. Artists enhance and elaborate the effects, whereas scientists contract and constrain them. Ever since Jan Evangelista Purkinje or Purkyne (1787 ^ 1869, figure 2) described the distortions that can be seen in gratings, concentric circles, and radiating lines, scientists have sought to account for their occurrence. The initial observations of the distortions have been attributed to Helmholtz so frequently (see Drysdale 1975; Millodot 1968; Mon-Williams and Wann 1996) that it is worth Guest editorial Perception, 2003, volume 32, pages 1029 ^ 1036