Radiance

Radiance is a measure of how much light energy is emitted from a surface, per unit area, in a specific direction. It reflects how bright a surface appears and is used in fields like physics, optics, and photography. In simple terms, it's a way to quantify light, taking into account both the intensity of the light and the angle at which it travels. Radiance is important for understanding how light interacts with objects, influencing how we perceive color and brightness in our environment.