Defining Kelvin Lumens and Lux

Kelvin

Symbol: K, is a unit of measure for temperature based upon an absolute scale. It is one of the seven base units in the International System of Units (SI). Kelvin is often used in the measure of the color temperature of light sources. Colour temperature is based upon the principle that a black body radiator emits light whose color depends on the temperature of the radiator. Black bodies with temperatures below about 4000K appear reddish, whereas those above about 7500K appear bluish.

Lumen

Symbol: lm, is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source. Luminous flux differs from power (radiant flux) in that radiant flux includes all electromagnetic waves emitted, while luminous flux is weighted according to a model of the human eye’s sensitivity to various wavelengths. Lumens are related to lux in that one lux is one lumen per square meter.

Lux

Symbol: lx, is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square meter.