Color Science Notes

How color and paint really work, for painters

These notes explain color the way a painter meets it: what the eye does with light, how a layer of paint makes a color, what happens when paints are mixed, and which parts of traditional color theory hold up when they are tested against real paint.

Everything here rests on measurements. Golden published the reflectance of 78 of its acrylics, and Okumura measured 26 matching colors from Golden’s Matte Fluid line mixed with white in steps. Those measurements feed a model that computes the color of any mixture of the 26, and the figures, the examples and the paint tools on this site all come from it.

Read the four parts in order if you are new to the subject, or jump to whatever you are curious about. Each lesson explains one idea in plain words. The equations behind it sit in a fold-out box at the end of the lesson, and nothing in the lessons depends on opening them.

Part 1

Color perception

Light and the spectrum, the three kinds of cone, why some colors look opposite, and how color is measured.

Part 2

How paint makes color

What light does inside a layer of paint, why some pigments hide and others glaze, and the model behind every mixture here.

Part 3

How paints mix

Mixing lines, why reds turn pink with white, why dark transparent paints come alive in a tint, glazes, darkening, and the split-primary palette put to the test.

Part 4

Color theory, tested

Primaries, color bias, the color wheel, complements, and warm and cool, checked against measured paint.

The paint tools let you mix any two of the 26 paints and watch the color move, or add white to a paint and see where its color is most vivid. The glossary explains every term in a sentence or two.

The same material is available as a single PDF, Color Science Notes, with the math in an appendix at the end of each part.