colormagnitude

Colormagnitude is not a standard term in color science, but in informal or applied contexts it often refers to the Euclidean length of a color vector in a given color space. In this sense, colormagnitude describes how far a color lies from the origin of the space, effectively measuring the overall intensity or strength of the color components.

Mathematically, if a color is represented as a vector c = (R, G, B) in a linear color space with components in the range [0, 1], the colormagnitude is the Euclidean norm: ||c|| = sqrt(R^2 + G^2 + B^2). A related value is obtained after linearizing a color that was stored or displayed with gamma encoding, since gamma-encoded components do not linearly correspond to light energy. In practice, many workflows first convert to a linearized color space before computing magnitude.

Colormagnitude is distinct from luminance or brightness. Luminance or luma is a perceptual measure of brightness that accounts for the differing sensitivity of human vision to red, green, and blue, and is not identical to the geometric magnitude of a color vector. Because human vision is nonlinear, the magnitude of a color vector does not reliably predict perceived brightness, especially across different hues or color temperatures.

Applications of the concept include color normalization, color-based segmentation, and analyses that require a scalar strength of color independent of direction in color space. Limitations include the lack of perceptual uniformity across spaces and the potential confusion with established terms like luminance or intensity. See also color space, RGB, luminance, and chromaticity.