lightnessvalue

Lightnessvalue is a general descriptor for the brightness component of a color as used in color science and digital imaging. It refers to the part of a color representation that controls how light or dark the color appears, independent of hue or chroma. The term is not tied to a single standard, but is commonly encountered in discussions of color spaces and color management.

Several color spaces implement a lightness or brightness component with different meanings and scales. In the perceptual spaces CIELAB and its cylindrical form CIELCH, lightness is represented by L*, on a 0 to 100 scale, where 0 corresponds to black and 100 to white. L* is derived from luminance relative to a reference white and is intended to be perceptually uniform, meaning equal steps roughly correspond to equal perceived brightness changes.

In the HSL (Hue, Saturation, Lightness) and HSV (Hue, Saturation, Value) models, the corresponding components are L or V. In HSL, L is computed as the average of the maximum and minimum of the normalized RGB components, yielding a 0–1 (or 0–100%) range. In HSV, V (value) is the maximum of the RGB components and represents a brightness level that does not map linearly to perceived lightness.

Because lightness in these spaces measures different properties, the terms can be used interchangeably in casual writing but may cause confusion in precise color work. Applications include digital color editing, color conversion between spaces, accessibility evaluation, and ensuring consistent appearance across devices. Understanding the differences among L*, L, and V helps interpret color values accurately.