Colorfulness, chroma and saturation are attributes of perceived color relating to chromatic intensity. As defined formally by the International Commission on Illumination (CIE) they respectively describe three different aspects of chromatic intensity, but the terms are often used loosely and interchangeably in contexts where these aspects are not clearly distinguished. The precise meanings of the terms vary by what other functions they are dependent on.Colorfulness is the "attribute of a visual perception according to which the perceived color of an area appears to be more or less chromatic ". The colorfulness evoked by an object depends not only on its spectral reflectance but also on the strength of the illumination, and increases with the latter unless the brightness is very high.
Chroma is the "colorfulness of an area judged as a proportion of the brightness of a similarly illuminated area that appears white or highly transmitting". As a result, chroma is mostly only dependent on the spectral properties, and as such is seen to describe the object color. It is how different from a grey of the same lightness such an object color appears to be.
Saturation is the "colorfulness of an area judged in proportion to its brightness", which in effect is the perceived freedom from whitishness of the light coming from the area. An object with a given spectral reflectance exhibits approximately constant saturation for all levels of illumination, unless the brightness is very high.
Original image, with relatively muted colors
L*C*h (CIELAB) chroma increased 50%
HSL saturation increased 50%; changing HSL saturation also affects the perceived lightness of a color
CIELAB lightness preserved, with a* and b* stripped, to make a grayscale image
In colorimetry, the Munsell color system is a color space that specifies colors based on three properties of color: hue, value (lightness), and chroma. It was created by Albert H. Munsell in the first decade of the 20th century and adopted by the United States Department of Agriculture (USDA) as the official color system for soil research in the 1930s.
Runge's Farbenkugel (Color Sphere), 1810
Albert H. Munsell
Several editions of the Munsell Book of Color. The atlas is arranged into removable pages of color swatches of varying value and chroma for each of 40 particular hues.