Lightness
How close a colour is to white or black.
Technical definition
In the HSL colour model, lightness is the average of the maximum and minimum RGB channel values, expressed as a percentage from 0% (black) to 100% (white).
Common confusion
Lightness and value (HSV) are calculated differently and can diverge for highly saturated colours.
Example
A pastel pink has high lightness; a deep burgundy has low lightness — both can share the same hue.
Why it matters
Lightness contrast between two colours is one of the main levers behind whether a pairing reads as subtle or bold.
Related terms
Sources
- CSS Color Module Level 4 — W3C (World Wide Web Consortium)