In optics, orange has a wavelength between approximately 585 -- 620 nm and a hue of 30° in HSV color space. In the RGB color space it is a tertiary color numerically halfway between gamma-compressed red and yellow, as can be seen in the RGB color wheel. The complementary color of orange is azure. Orange pigments are largely in the ochre or cadmium families, and absorb mostly blue light.

Varieties of the color orange may differ in hue, chroma (also called saturation, intensity, or colorfulness) or lightness (or value, tone, or brightness), or in two or three of these qualities. Variations in value are also called tints and shades, a tint being an orange or other hue mixed with white, a shade being mixed with black. Orange was one of the original colors formulated by Crayola in 1903.

Orange pigments are largely in the ochre or cadmium families.