Color Wheel & Theory Basics
The reference every harmony scheme in the generator is built from, with live examples of each one.
Primary, secondary, and tertiary colors
In traditional paint mixing, red, yellow, and blue are the primary colors: the starting points that can't be created by mixing anything else. Mixing two primaries gives you a secondary color, orange, green, or purple. Mixing a primary with a neighboring secondary gives you a tertiary color, like red-orange or blue-green.
Warm vs. cool colors
Warm colors sit on one half of the wheel and read as energetic and advancing. Cool colors sit on the other half and read as calm and receding. The split isn't perfectly even, green and purple both sit near the boundary and can lean either way.
Warm
Cool
Color harmony schemes
Each of these is a rule for picking colors that are positioned deliberately around the wheel, rather than at random. They're the same rules behind the generator's Harmony Builder mode.
What makes colors clash
Colors tend to clash when they're close enough on the wheel to compete but not similar enough to feel intentional, and far enough apart in saturation or lightness to fight for attention without a clear hierarchy. Following one of the schemes above, or keeping one color dominant with the rest as accents, is the most reliable way to avoid it.