Colour matching is not colour mixing

Anyone can mix a colour that matches wet. The bench standard is different: the recipe must match after it dries, after it cures, and under three lights — daylight, the warm lamp of a majlis, and the cold white of a car park.

Metamerism, the saboteur

Two colours can agree under one light and argue under another. That failure has a name — metamerism — and the only defence is testing on the hidden panel first, then living with the swatch for a day before committing the piece.