A system of surface-color specifications based on perceptually uniform colour scales for the three variables. Munsell hue, Munsell value, and Munsell chroma. For an observer of normal colour vision, adapted to daylight and viewing the specimen when illuminated by daylight and surrounded with a middle grey to white background, the Munsell hue, value, and chroma of the colour correlate well with the hue, lightness, and perceived chroma.