5 August 1999

The Accidental Scientist

by Kate Melville

Have you ever seen the gigantic 'block portraits' by Chuck Close? If you have you may have been looking at a paintings that are creating an interesting scientific debate. In the August issue of Science, Denis G. Pelli a New York University professor of psychology and neural science,challenges the notion that shape is seen the same way at all sizes. In Close's paintings the edges of individual blocks of colour blur together as a viewer backs away. However according to Pelli, the transition from a grid to defined object occurs at relatively short distances from the canvas (less than six meters). At these distances, the individual blocks are still in sharp focus for a person with normal vision.

Pelli argues that the dramatic effect of viewing distance on the appearance of Close's paintings shows that perception of shape depends on visual size. The data for this was collected at the Close Retrospective, held at the Museum of Modern Art (New York) in 1998 (the retrospective is now showing at the Hayward Gallery in London until September 19). Interestingly the main experiment only used a tape measure, but Pelli says, "It is commonly assumed that scientific research today can only be done in laboratories with complex equipment. But the essence of science is careful observation of the world around us. And in this sense, the best science and the best art share a common methodology".

Pelli argues that Close was as much of a scientist as he was an artist, "One might suppose that he was a naïve artist, obsessed by grids, who innocently produced the coarsely gridded paintings that we use here to reveal the size dependence of shape perception. In fact, Close has devoted his career to studying just that . . . He was more thorough than his scientific colleagues; the size of the marks in his block portraits increased by 15 percent per year from 1973 (0.4 cm) to 1997 (9 cm). He made sure that exhibitions of his work would convey the idea, canceling a retrospective that could not provide long viewing distances. So credit Chuck Close with discovering this size-dependent breakdown of our ability to extract shape from shading, well within the bounds of our visual field and acuity."