hslHue

hslHue refers to the hue component of the HSL color model, which stands for Hue, Saturation, and Lightness. In this model, hue describes the type or quality of color, while saturation indicates vividness and lightness indicates brightness. Hue is depicted as a position on a circular color wheel, with red at 0 degrees, green around 120 degrees, and blue around 240 degrees. The hue value determines the color identity independent of how saturated or light it is.

In digital contexts, hue is typically expressed as an angle from 0 to 360 degrees, and the value is cyclic, meaning 360 degrees is equivalent to 0 degrees. In CSS and many color tools, colors are specified with the syntax hsl(hue, saturation, lightness), where hue is given in degrees (for example, 120deg for green). Some systems also support other angle units such as turns, radians, or gradians.

Adjusting the hue while keeping saturation and lightness constant rotates the color around the wheel, changing its perceived color type. A 180-degree shift yields the complementary color. Hue changes are not always perceptually uniform; the same degree shift can feel different depending on the region of the wheel and the surrounding colors.

HSL hue is widely used in color pickers, design systems, and CSS styling for creating palettes and performing hue-based transformations. It also relates to other color spaces, such as HSV, and to perceptually tuned variations like HSLuv, which aim to improve uniformity in color perception.