hue

Hue is a fundamental attribute of color that allows us to distinguish color families such as red, green, and blue. In physics, hue roughly corresponds to the wavelength of visible light, with red occupying the long-wavelength end and violet the short-wavelength end of the spectrum. Perceptually, hue is the aspect of color that people name when they say a color is red, blue, or green, and it is influenced by lighting and context.

In most color models used in art, design, and digital imaging, hue is one of three basic attributes, alongside saturation (intensity) and brightness or lightness. In hue-saturation-lightness (HSL) and hue-saturation-value (HSV) models, hue is represented as an angle around a color wheel, typically 0 to 360 degrees. Adjusting hue changes the color family while keeping saturation and brightness constant, enabling smooth transitions around the wheel.

Hue differs from shade, tint, and tone, which describe variations in lightness and/or saturation of a given hue. Color wheels organize hues into primary, secondary, and tertiary groups, with traditional primaries varying by medium (for example, red, yellow, blue in pigment theory; red, green, blue in additive light systems).

Perception of hue can be altered by illumination, viewing conditions, and simultaneous colors, a phenomenon known as metamerism. Hue is thus a perceptual and physical property used in color naming, matching, and specification in art, design, imaging, and digital media.