Black and white are gradual colors

Quick answer：

The statement 'Black and white are gradual colors' seems to suggest a misunderstanding. In color theory, black and white are considered to be achromatic colors, which means they do not contain hue. They are not considered gradual colors in the sense of being shades of a single color. Gradual colors typically refer to a range of tones from light to dark within a single hue, such as shades of blue or red.