Hu

16°28N 107°35E, pop (2000e) 310 300. Town in Binh Tri Thien province, C Vietnam; near the mouth of R Hué, 8 km/5 mi from the South China Sea; ancient town, part of the Chinese Empire; former capital of Annam and of the Vietnamese Empire; many historical sites destroyed in Vietnam War; railway; university (1957); commerce, rice, timber, textiles.

A hue refers to the gradation of color within the visible spectrum, or optical spectrum, of light. "Hue" may also refer to a particular color within this spectrum, as defined by its dominant wavelength, or the central tendency of its combined wavelengths.

In painting color theory, a hue refers to a pure color —one without added white (tint) or black (shade) pigment. A hue is a color on the Color wheel.

In an RGB color space, hue can be thought of as an angle φ in standard position. To calculate φ, let R, G, B be the color coordinates in RGB space, defined on a scale from zero to one. Then, after obtaining the brightness μ and the saturation σ, the hue could be obtained from

(Compare with standard score).

The RGB coordinates should be derivable from the μ, σ, φ coordinates as follows:

Hue is a coordinate (an angle of rotation) in HSL color space and HSV color space.

Manufacturers of pigments use the word hue e.g.