Mitsuo IKEDA^1,2*, Pontawee PUNGRASSAMEE¹, Pichayada KATEMAKE¹ and Aran HANSUEBSAI¹

¹Department of Imaging and Printing Technology, Chulalongkorn University, Bangkok 10330, Thailand
²Department of Photonics, Ritsumeikan University, Nojihigashi, Kusatsu, Shiga 525-8577, Japan

(Received March 7, 2006; Accepted May 24, 2006)

Color appearance was measured for a test patch which was placed in a test room illuminated by the daylight type of illumination and was looked at from the subject room illuminated by one of the four colored illuminations, red, yellow, green, and blue, through a window of three different sizes. When the window was the smallest so that only the test patch was seen within the window the color of the test patch appeared almost opponent to the illumination color, but as soon as something is seen within the window of larger size the color returned to the original color of the test patch to indicate the color constancy. To recognize the test room as a space was essential to perceive the real color of the test patch. This returning to the original colors was not influenced by green color of objects densely placed in the test room or by red color of objects again densely placed in the test room. The results imply that the color appearance of the test patch is not determined by the retinal chromatic adaptation, but by the brain adaptation to color of the illumination in the space.

Key words: color appearance, color constancy, chromatic adaptation, space recognition, illumination, recognized visual space of illumination

^*E-mail address: kay0505mitsuo_ikeda@ybb.ne.jp