/01 Building a colour scheme from one colour
Pick a base colour and get the classical harmonies derived from it — complementary, triadic, analogous, split-complementary and tetradic. Each is a different rule for choosing hues that sit at fixed angles around the colour wheel.
Starting from one colour and deriving the rest keeps a palette coherent, which is much harder to achieve by picking swatches one at a time.
/02 Which harmony to reach for
Analogous schemes use neighbouring hues and feel calm and unified, but offer little contrast for emphasis. Complementary pairs sit opposite each other and give maximum separation — strong for calls to action, exhausting across large areas.
Split-complementary keeps most of that contrast while softening the clash, and triadic schemes stay vivid and balanced. A common approach is to let one hue dominate, use a second for support, and reserve the opposite hue for the few things that must stand out.
/03 What color harmony means
Color harmony is the idea that some colour combinations look balanced because of where the colours sit on the colour wheel. The relationships are geometric: colours directly opposite each other, next to each other, or evenly spaced around the wheel tend to work together, which gives you a reliable starting point instead of trial and error.
Pick one base colour and this generator builds every classic harmony from it at once. Complementary uses the colour opposite, for maximum contrast. Analogous uses neighbours, for calm schemes. Triadic spaces three colours evenly, for lively but balanced palettes. Split-complementary pairs the base with the two colours beside its opposite, softer than a straight complementary. Tetradic uses four colours in a square, and monochromatic keeps one hue at different lightness levels. Compound, double complementary, pentadic and golden ratio variations are there too for less common schemes.
/04 Turning a harmony into a usable palette
A harmony tells you which hues belong together, not how much of each to use. Most successful designs follow a 60-30-10 split: one dominant colour for large areas, a secondary colour for supporting elements, and a small amount of accent for buttons and highlights.
Equal amounts of complementary colours tend to vibrate uncomfortably, so let one lead and use its opposite sparingly. Adjust lightness freely, since a harmony still reads as harmonious when one colour is pale and another deep. Then check text colours for contrast separately, because a harmonious pair can still fail readability.