The Munsell Color System
The Munsell Color System is a color space that specifies colors based on three color dimensions: Hue, Value (lightness), and Chroma (color purity). It represents the closest attempt at representing the color solid of surface colors by samples, spaced at equal sensation intervals.
Hue
The attribute of visual sensation which distinguishes colors like red, blue, green, yellow, and purple. Denoted by letters (R, YR, Y, GY, G, BG, B, PB, P, RP) with prefix numbers (2.5, 5, 7.5, 10).
Example: 7.5R means red inclined towards yellow-red
Value
The estimated lightness of any surface color on a scale of 10 equal sensation intervals extending from ideal black (value = 0) to ideal white (value = 10).
Example: Value 9 denotes a very light color
Chroma
The estimated pure chromatic color content of a surface color on a scale of equal sensation intervals extending from grey (Chroma = 0).
Example: Chroma 2 indicates low strength of color
Complete Munsell Reference
A complete Munsell reference is written as: Hue Value/Chroma
For example, 7.5R 9/2 means:
- Hue of 7.5R (red inclined towards yellow-red)
- Value 9 (very light color)
- Chroma 2 (low color strength)
- Overall description: Pale pink
CIE Chromaticity Coordinates
Chromaticity coordinates are ratios of tristimulus values that indicate the color quality of a sample. The CIE (Commission Internationale de l'Éclairage) system uses x and y coordinates to specify color in a two-dimensional space.
Calculation
x = X / (X + Y + Z)
y = Y / (X + Y + Z)
z = Z / (X + Y + Z)
Where X, Y, Z are tristimulus values in the CIE 1931 Standard Colorimetric System
Standard Illuminant: D65 — Average north sky daylight with color temperature 6,500K
CIE L*a*b* Color Space
The CIE L*a*b* color space is designed to be perceptually uniform, meaning that a change of the same amount in a color value should produce a change of about the same visual importance.
L* (Lightness)
Ranges from 0 (black) to 100 (white). Represents the perceived lightness of the color.
a* (Red-Green)
Positive values indicate red direction, negative values indicate green direction.
b* (Yellow-Blue)
Positive values indicate yellow direction, negative values indicate blue direction.
Glossary of Color Terms
Hue
Attribute of visual sensation which has given rise to color names, such as blue, green, yellow, red, and purple.
Chroma (Colour Content)
The subjectively estimated amount of colorfulness seen in the visual sensation arising from a surface color. Similar to chroma in the Munsell system, it represents the purity or saturation of a color.
Value (Lightness)
Attribute of color perception by which a white object is distinguished from a grey object and a light-colored object from a dark-colored object.
Achromatic Sensations
Visual sensations devoid of the attribute of hue (white, grey, and black).
Chromatic Sensations
Visual sensations possessing the attribute of hue (colors other than white, grey, and black).
Full Colour
Surface colors which are produced with the maximum colorfulness obtainable.
Warm Colours
Red, orange, or yellow, or colors which exhibit a predominance of these.
Cool Colours
Green or blue, or colors which exhibit a predominance of these.
Tint
The weak color resulting from the addition to white of a small amount of coloring matter.
Shade
A color of the same hue and saturation but lower luminosity.
Tone
A slight variant of a color.
Masstone
The color by reflected light of a bulk of undiluted pigment.
Undertone
The color of a pigment when it is used in very thin layers or greatly extended with white, the hue of which may often differ from that of the masstone.
Luminance Factor
The ratio of the luminance of a body while illuminated and observed under certain conditions to that of a perfect diffuser under the same conditions.
Complementary Colours
Additive: Any two colors which, by additive mixture, can be made to match a specified achromatic color.
Subtractive: Any two absorbing media which, by subtractive mixture, can be made to match specified achromatic color.