Abstract
Lightness of rooms rated by visual sense is no doubt largely affected with the holizontal illumination and the mean brightness in the whole visual field. But besides, we had a prospect that it would be affected with the shapes of rooms too. In other words, the adequat value of illumination or the mean brightness might differ from each other according to the hight or the width or the width or the depth of each room. We took for samples 18 concourses of railway station in Tokyo and its neighbourhood, and measured the mean horizontal illumination and the mean brightness in the whole visual field by a person standing at the centre of its entrance, and at the same time we (nine persons) memorized the psychological value of ligthness of each room in 7 grades. The relation between that psychological value of lightness and the shapes of rooms, especially the depth of room, is seen at Fig.8〜13. It would be concluted certainly from the results that the paychological value of lightness decrease according to the depth of room. Besides, the adequate value of the mean horizontal illumination and the mean brightness in the whole visual field were also obtaind. Fig.6 and 7 show these value, which are about 330lx and 150ml (meter Lambert).
