Simply put, luminance describes the amount of light that is emitted from, passed through, or reflected off an object. It is measured using candela per square meter, which is the concentration of luminous intensity per unit area in a specific path. Luminance is often confused with brightness. While the two concepts are similar, there are some striking differences. Luminance is something that can be measured with a luminance meter. It is an objective and a definite fact that can be tested several times over. Brightness, however, is subjective and something that is perceived by the human eye. It cannot be measured by any formula.