Secondary and tertiary colors, mixed in paint and in light

The painters' wheel (RYB) starts from red, yellow and blue. CMY starts from cyan, magenta and yellow. RGB starts from red, green and blue light, the three lamps of a screen. The swatches show the stand-in colors this site uses for each set; the first two are paints, the last is light.

Paint mixes subtract light, and the paint model works on our stand-in paints, not on any brand. Each pair below is mixed in equal parts.

Lights add. Two lamps shining together give the colors below.

A tertiary color sits between a primary and a secondary, which gives six. The wheel column shows where each one lies on the painters' wheel: the red stand-in turned by a fixed angle, keeping its saturation and lightness. The paint column mixes the primary and its neighboring secondary in equal parts instead.

The two columns answer different questions, so they are allowed to differ. The wheel column says which direction a color lies in. The paint column says what two stand-in paints give when you mix them.

Red and blue paint come out dark and dull in our model, a reddish purple with little brightness. The same two colors as light come out as a bright magenta. Paint takes light away and light adds it, so the same two names give two very different results.

Within the paint model, the CMY pairs give a blue-purple and a green that are more vivid than the purple and green of the RYB pairs, and an orange-red that is about as strong as the RYB orange.

For red-orange, yellow-orange, yellow-green and blue-violet, the wheel position and the paint mix land close to each other in hue. For blue-green and red-violet the paint mixes come out much darker and duller than the wheel positions, and the red-violet mix leans toward red. A wheel position is a direction, not a recipe.