Color Theory

Color theory is the set of rules people have invented for predicting what happens when two colors sit next to each other. It is less a science than an accumulated body of studio advice, but the useful parts are surprisingly durable.

The wheel

Newton bent the spectrum into a circle in 1704 so that red could touch violet, and almost every color system since has been an argument about that circle. The painter's wheel puts red, yellow, and blue at the corners; the light wheel uses red, green, and blue; the printer's wheel uses cyan, magenta, and yellow. They disagree because they model different physics — pigment subtracts light, screens add it.

Three dimensions

Any color can be described by hue (where it sits on the wheel), saturation (how far it is from grey), and lightness (how much light it reflects or emits). Most bad color work is a hue problem pretending to be a lightness problem: two colors that clash often just have the same lightness, so the eye cannot find an edge between them.

Harmony schemes

Complementary pairs sit opposite each other and produce maximum contrast — good for a single accent, exhausting across a whole page. Analogous schemes take three neighbors and read as calm and unified. Triadic schemes take three evenly spaced hues and stay lively without tipping into noise. Split-complementary is the safe default: one base hue plus the two neighbors of its opposite.

Why RGB math lies

Averaging two RGB values does not give you the color halfway between them, because RGB is not perceptually uniform — a step of 10 in a dark blue looks nothing like a step of 10 in a bright yellow. Perceptual spaces such as CIELAB, OKLab, and OKLCH re-map the numbers so that equal numeric distance means roughly equal visual distance. If you are generating palettes programmatically, interpolate there and convert back at the end.

Context beats the swatch

Josef Albers spent a career demonstrating that a color has no fixed identity: the same grey looks warm on a blue field and cold on an orange one, and two different greys can be made to look identical. Simultaneous contrast means you should never judge a color in isolation — always in the layout it will actually live in, at the size it will actually appear.

The practical version of all of this: pick one hue, earn every additional one, and let lightness do the structural work.