Three colours spaced evenly around the colour wheel.
Three hues separated by 120° from each other.
A triadic scheme is not the same as picking three random bold colours — the even spacing is the defining feature.
Red, yellow and blue form a triadic set.
Triadic schemes are a common way to get strong contrast while keeping some balance, used often in branding.
A triad is three hues 120° apart. On the HSL wheel a triad built on a primary is the three primaries themselves, and one built on a secondary is cyan, magenta and yellow. The painter's triad of red, yellow and blue comes from a different wheel on which those three are the evenly spaced set. In both cases the construction fixes hue only, and lightness and chroma are left to the designer.
| Colour | HSL hue | CIELAB L* | CIELAB chroma |
|---|---|---|---|
| Base #ff0000 | 0° | 53.2 | 104.6 |
| 120° on #00ff00 | 120° | 87.7 | 119.8 |
| 240° on #0000ff | 240° | 32.3 | 133.8 |
The three hues are exactly 120° apart and all have 50% HSL lightness, but their measured lightness runs from L* 32.3 (#0000ff) to 87.7 (#00ff00). Used in equal areas the lightest member dominates. Working triads give one member most of the area and bring the other two down in chroma or size.
How this was calculated: The catalogue Red with 120° and 240° added to its HSL hue, then each converted to CIELAB under D65.
A logo or a children's product uses a full-strength triad in equal parts.
The members differ so much in lightness that one of them, usually the yellow or green, takes over, and the darkest fails contrast against dark backgrounds while the lightest fails against white. The scheme needs a separate rule for which colour carries text.