Explaining Looks

Abstract

In 1824, the French chemist M. E. Chevreul travelled to the Gobelin tapestry works to respond to complaints of the weavers that some of the dyes were inferior, and rapidly faded or changed in hue after a tapestry was completed. Chevreul determined that some of the complaints were well-founded, and embarked on some of the early chemical investigations on the stability of coloural pigments. Other complaints seemed to have no basis in chemistry. Chevreul eventually demonstrated that such shifts in hue were not caused by any change in the threads, but were a perceptual effect arising within the weaver. He provided some of the earliest experimental demonstrations of what are now called colour contrast effects. Since its birth in Chevreul's day, the experimental psychology of perception has uncovered many such effects. This chapter also discusses edge enhancement effects, the Hermann grid, and colour adaptation. It looks into explanations of why something appears to have a quality it lacks.