抄録
In the previous paper, the author proposed the use of C* value as the method of expressing numerically the depth of chromatic colors, but the problem to calculate such achromatic colors as white, grey and black still remained to be solved. In this paper, this subject is discussed.
It is confirmed in the present study that all achromatic colors except for white and very light grey very close to white can be expressed numerically by regarding them as the shades which belong to hue of 5PB.
It is also shown that the depth series of Munsell achromatic axis can be adequately approximated by the following equation, where, V is the Munsell Value.
Therefore, it is concluded that Munsell achromatic axis changes in arithmetic progression for brightness, while it changes in geometric progression for depth.
