Painters long mixed colors by combining relatively bright pigments with black and white. Mixtures with white are called tints, mixtures with black are called shades, and mixtures with both are called tones. See Tints and shades.[1]
A color solid is the three-dimensional representation of a color space or model and can be thought as an analog of, for example, the one-dimensional color wheel, which depicts the variable of hue (similarity with red, yellow, green, blue, magenta, etc.); or the 2D chromaticity diagram (also known as color triangle), which depicts the variables of hue and spectral purity. The added spatial dimension allows a color solid to depict the three dimensions of color: lightness (gradations of light and dark, tints or shades), hue, and colorfulness, allowing the solid to depict all conceivable colors in an organized three-dimensional structure.