Perceived lightness in different illumination space through various sizes of aperture

Abstract

This research aims to investigate the effect of aperture on perceived lightness in different illumination space. Two rooms were constructed to obtain different illumination space: subject room (front) and test room (back). The wall between the rooms has a window through which the subject could see the test room. The achromatic test patches had two patterns: the square (A) and the square with a corner cut off (B). These test patterns were modified from Gilchrist’s experiment. Subjects could perceive the test patch in different positions with the shapes of test patterns. The masks were made for controlling the open area that subject could see through test room. Subject judged lightness of test patch, Patterns A and B through various sizes of aperture in percentage of whiteness and blackness. This research was done with real scene and a picture of the real scene that was seen through a viewing box. The results showed that when subjects were limited to see only one space, i.e. front room, the perceived lightness of both test patch patterns were the same. Whenever the subject could see even the small area of the other space illumination around the test patch, the perceived lightness of both test patches were different. The perceived lightness was determined by the recognition of the space illumination.