What is a Lumen

The Lumen (symbol: lm)
Is the SI unit (International System - International Metric). It measures the power of light as perceived by the human eye. The luminous flux differs from the radiation flux, and measures the total output of the light. The Lumen is defined in relation to the Candela.
lm = cd X sr (where sr = solid angle).
The Lux (symbol: lx) (Luxe).
Is the SI unit (International System - International Metric System) lighting and light emission. Used in photometry as a measure of light intensity, which falls or passes to a surface, per square meter, as perceived by the human eye.
lux = lm/m²
The Kelvin (symbol: K) (Kelvin).
The variation in color of the cooler and a warmer color temperature, is known as the Kelvin scale. The colder the colors the higher the color temperature, and the lower the color, the color temperature is lowered.
Due to different materials, light sources emit light of different colors. This is measured in Kelvin degrees and practically shows how hot (in yellow) or cold (in blue) is the color emitted by the respective light source.
Warm white, Soft white, Warm white ≤ 3,000K
White, Bright White, White> 3.500K
Cool white, Cold White> 4.000K
Daylight, Daylight ≥5.000K
An incandescent lamp has a light, whose temperature usually ranges between 2700K and 3300K.