Differences between the LCH Color Space and the Cube

Alongside the similarities by the criteria hue, lightness and saturation, there are also fundamental differences between the cube model and the LCH color space.

The Cube Describes the Color Model

The cube always requires as a reference point primary colors, from which all other colors can be derived when mixed. Thus, the cube's practical application is describing the ratios of a set group of colors. A color value scale is one example.

However, the cube is unsuitable when mixtures of two groups of primary colors of different orgins need to be compared. The blue on a monitor has the same position in the cube as the blue in print. However, in direct comparison, the two blue tones vary very much from each other.

The LCH Color Space Describes the Color Order

Because the LCH color space describes the conversion of color spectra by the attribute hue, lightness and saturation, it functioins without primary colors. With it, the differences between primary colors of varying origins and between any mixed colors can be determined exactly.

--Digital Color Management, Jan-Peter Homann, Page 42