Effect of Print Contrast on Reflected Glare

Reducing reflected glare on visual tasks, such as prints in offices, is one of the most important factors in office lighting. Experimental studies the authorsre carried out to reduce the reflected glare. The authors studied, through a subjective evaluation, to obtain permissible limit of reflecting source luminance, and found relationships among various lighting factors: permissible limit of light source luminance, illuminance on visual task, luminance contrast between character and background, and print contrast(luminance contrast between character and background without reflected glare). (1) Print contrast had considerable effect on the same contrast with reflected glare superposed. The latter required higher luminance contrast without reflected glare with the same background luminance. (2) Accordingly, with different luminance contrasts without reflected glare, legibilities of character with reflected glare are different, even with the same background luminance and luminance contrast.