Editing Natural Color System (section)

=== Saturation and lightness ===
In addition to the above values ''s'' (blackness), ''w'' (whiteness), ''c'' (chromaticness) and ''Φ'' (hue), the NCS system can also describe the two perceptual quantities [[Colorfulness#Saturation|saturation]] and lightness. NCS saturation (''m'') refers to a color's relation between its chromaticness and whiteness (regardless of hue), defined as the ratio between the chromaticness and the sum of its whiteness and chromaticness <math>m = c / (w + c) = c / (100 - s)</math>. The NCS saturation ranges between 0 and 1.

For the example color of '''S 2030-Y90R''', the saturation is calculated as 
: <math>m = c / (100 - s) = 30 / (100 - 20) = 30 / 80 = 0.375.</math>

NCS lightness (''v'') is a color's perceptual characteristic to contain more of the achromatic elementary colors black or white than another color. NCS lightness values varies from 0 for the elementary color black (S) to 1 for the elementary color white (W). For achromatic colors, that is any black, gray or white with no chromatic component (''c'' = 0), lightness is defined as 
: <math>v = \frac{100 - s}{100}.</math>

For chromatic colors, the NCS lightness is determined by comparing the chromatic color to a reference scale of achromatic colors (''c'' = 0), and is determined to have the same lightness value ''v'' as the sample on the reference scale to which it has the least noticeable edge-to-edge difference.