By Mitsuo Ikeda and Chanprapha Phungsuwan
When a subject looked at a uniform white board placed in a test room from a subject room through a large window the window appeared a mere black sheet if the former was illuminated very low while the latter was illuminated high. If an object was placed just in front of the white board the board immediately appeared a white board. This indicates that the object worked as the initial visual information IVI for the subject to construct a recognized visual space of illumination RVSI for the test room. If, however, the object was gradually separated from the surface of the board the power of the object as the initial visual information decreased and the whiteness decreased. In this paper the power of an object as the initial visual information was investigated as a function of the distance of the object from the white board. A subject judged the amount of whiteness of the board by the elementary color naming. It gradually decreased from 80 % down to 10 % or less when the object was changed from 0 cm to 86 cm.