Contextual effects on real bicolored glossy surfaces.

The material property of glossiness, which is attributed to many objects in our daily life, is physically independent of the objects' color. However, perceived glossiness can change with the contrast between the highlight and the area around the specular highlight. Hitherto, experiments mainly investigated gloss on unicolored surfaces. It is well known that the context in which a surface is embedded can influence its perceived lightness. Here we investigated whether similar contextual effects exist also for gloss perception by presenting single surfaces containing two different colors. We tested the influence of the second color on participants' gloss judgments with both real surfaces and photographs of those surfaces. In both conditions, participants were influenced by the second color on the surface even though they were asked to ignore it. We found contrasting contextual effects on the bicolored surfaces. However, when explicitly asked to rate the global gloss on the bicolored surfaces, participants took both parts of the surface equally into account.