Color discrimination ellipses measured by Brown and MacAdam are transformed into the CIE-UCS U*V*W*and modified Adams system. From these results the relations between lightness difference and chromaticness difference are checked in the U* V* W* color solid, and new relations between lightness and chromaticness difference in the uniform color solid are written as, U'=6W* (μ-μ0), V'=6W* (ν-ν0). From this result and Hioki and Sato's result a new system
W''=25Y1/3-17
L''=13 (W'') 5/6 (μ-μ0)
V''=13 (W'') 5/6 (ν-ν0)
is proposed.
