Some researches show the results that the color of light affects landolt C performance, and increasing the relative contribution of short-wavelength (blue) light will reduce pupil size and increase visual acuity. The research object is to investigate the effect of color of the light on brightness. The results are as follows: Among the 14 colors we used, the B/L ratio of blue light is the biggest, and then is green, red, white, yellow and color of lamp. But except for blue, the significant difference on brightness between green, red, yellow and white is not found. However, under the same luminance level, blue light is significantly brighter than white light and the other colors we used. On the other hand, according to the research reported by Ayama M., the brightness will increase when the purity of color of light increases. However, in our study, only B/L ratio of blue light increases when the purity increases. Because the blue light is significantly brighter than white light, in the future, it is possible to reduce luminance levels and increase energy savings while maintaining the same level of brightness.
