Apparent brightness and its application to illuminating engineering

Proposed scales of apparent brightness are introduced, which were reported by S. S. Stevens and R. G. Hopkinson. Procedures for designing visual environment were briefly stated on the basis of the scales of apparent brightness.The present authors propose following further studies on the application of apparent brightness to illuminating engineering: 1) Consideration of effect of brightness contrast and constancy in addition to adaptation on prediction of apparent brightness. 2) Relations between visual functions and apparent brightness. 3) Specification of pleasant or comfort distribution of apparent brightness in visual environment. 4) Specification of the design procedure of visual environment based on apparent brightness for easier use. 5) Necessity to use apparent brightness meter, which is similar to the color appearance meter desingned by R. W. G. Hunt. 6) Necessity of interim international unification of scales of apparent brightness. 7) Necessity to establish the system to appraise visual environment subjectively, which woluld calrify the relation between the pleasantness (or comfortability) and apparent brightness.