Quantitative method to evaluate of evaluation item in 2-D composition that is one of the education about basic design has been reported in current our research. However, the unity of color of the composition object has not been investigated. Then, we experimented on psychology that examined the influence on the settlement feeling when we changed brightness on each color side by the achromatic color for the composition with a high evaluation of the settlement of the form 60 kinds that changed 3 composition object patterns, 4 brightness patterns, and 5 arrangement of color patterns respectively were prepared as experiment stimulation. The unity was answered by using the rating scale method for the subjects. Influence that difference of brightness on each color side of composition object gives unity is examined from the outcome of an experiment.