抄録
We examine how a seven-color cyclic sequence affects human color impression. In order to investigate the different effects of two sequences, we consider a hexagonal diagram that is a projection of RGB color space from white to black The hexagonal diagram corresponds roughly to the hue circle indicated by both hue and saturation in the HLS system. If i) the projected route is approximately the minimum, ii) each saturation is large, and iii) neighboring colors are not too close each other, the projected route area is assumed to be large. In other words, the projected route area indicates the magnitude of naturalness (as in rainbows) for color sequences. The minimum sequence is similar to the order of colors in rainbows. On the other hand, the non-minimum sequence is completely different. Although the seven colors used in the present study are not distributed as in rainbows, and the seven-color cyclic sequences are not continuous sequences having gradation, we propose a human color impression model using the projected route area indicated by both hue and saturation. In the proposed model, the subject has natural impressions when the route area is large and unnatural impressions when the route area is small.
