Pigments create color by subtracting wavelengths, while lights create color by adding wavelengths together.

The longer version

A pigment is a filter: it removes certain wavelengths from whatever illuminates it and returns the rest, which is why the same paint shifts under different lamps. Light sources are the opposite, because each beam contributes energy of its own, and overlapping beams accumulate rather than cancel.

So the primaries differ. Additive mixing starts from darkness and builds toward white with red, green, and blue; subtractive mixing starts from white and strips away, using cyan, magenta, and yellow. Stage lights follow the first rule, printed ink the second, and confusion arises when people assume one rule covers both.

Where this entry sits

These facts explore how light behaves and how human eyes turn it into the colors we see. Along the way you meet rainbows, prisms, mirrors, shadows, lasers, and optical tricks that fool our vision every day. The full list sits on the Color and Light page, where every entry is listed in order.