Luminance is a measure of the brightness of a surface as perceived by the human eye. It quantifies how much light is emitted, reflected, or transmitted from a particular area in a specific direction. The unit of measurement for luminance is the candela per square meter (cd/m²), which helps in comparing the brightness of different light sources or surfaces. In practical applications, luminance is important in fields like photography, television, and lighting design. It influences how we perceive images and scenes, affecting contrast and visibility. Understanding luminance helps in creating better visual experiences in various media and environments.