Color Temperature (Unit: K (Kelvin))

Color temperature is conventionally stated in Kelvin (K), the unit of absolute temperature. The color temperature is the temperature that makes an ideal black body radiator radiate comparable hue as the light source. Usually, color temperatures over 5,200K are called cool colors, color temperature below 3500K are called warm colors. Warm white LED colors provides more cozy and relax atmosphere and are typically used for living and bed rooms while cool white LED lights set more focus and serious tones for working spaces like engine room and pilot’s cockpit. Recently more and more lights have designed with dual color temperature (warm and cool white) so end users and choose the right color temperature (3000K, 4000K or 6000K) whenever they need it.

Luminous Flux (Unit: lm(lumens) )

The total amount of light emitted from a lamp. The higher lumen is, the more intense the light output. Luminous Flux does NOT vary with distances. Normally the lumen reflects the capability of lighting a light fixture is able to provide – the lighter the lumens are the brighter the light fixture is.

Illuminance (Unit: Lux )

Illuminance is the total luminous flux falling on a surface. It shows the intensity of the incident light. Mathematically, Illuminance (Lux) = Lumens (lm) / area(m^2) where area is the illuminated area of the light source. The farther the surface are away from the source, the larger the area would be, and hence the smaller illuminance, while the Luminous Flux remains the same.

Example:

If a light fixture with 100 lumens lights up an area of 1 square meter, the Illuminance would be 100 lux. If, however, the same fixture lights up 10 square meters (at a farther place), the illuminance would be reduced to only 10 lux.

With the same distance to the lighting source, the smaller beam angle also results in brighter Illuminance as the lights are more focused. So for example a light with 1000 lumen with wider beam angle would light up 10 square meters at a certain distance, resulting in 100 Lux illuminance. Another light with same 1000 lumen but smaller beam angle and lights up 1 square meter at that distance, would have an illuminance of 1000Lux in that area.