Brightness refers to the perception of how much light is emitted or reflected from a surface. It is a key aspect of visual perception and is influenced by factors such as the intensity of the light source and the color of the object. Brightness is often measured in units like lumens or candelas, which quantify the amount of light produced. In everyday life, brightness affects how we see and interact with our environment. For example, a brightly lit room can enhance mood and productivity, while dim lighting may create a cozy atmosphere. Understanding brightness is essential in fields like photography, design, and lighting engineering to achieve desired visual effects.