USABLE LIGHT = LUX
The Lux is the unit of illuminance and it is an indication of how much light is incident on a surface. One Lux is defined as an illuminance produced when one lumen is incident on one square meter area, so one Lux is one Lumen per square meter area
The illuminance on a bright day is 100,000 lux. A televised football match requires an illuminance of around 16,000 lux. A kitchen requires around 500 lux. A public road at night requires around 30 lux.
TOTAL LIGHT OUTPUT = LUMENS
RAW LUMENS VS EFFECTIVE LUMENS
This is a measure of the theoretical output of a light. Raw Lumen output is calculated by multiplying by the theoretical rated output of the LEDs by the number of LEDs in the lamp.
6 LEDs rated at 150 Lumens per watt. 6 x 150 = 900 Raw Lumens
Light source placed into lumen sphere to measure the complete output of a source
This is a measure of the actual output of a light. The Effective Lumen output takes into consideration electrical and real world losses(ex.thermal, optical, and assembly), so it is a better representation of the useful visible light that is actually produced.
Raw Lumens = 800,Thermal, Optical & Assembly Losses = 40% (of Raw Lumens) 800 – 320 = 480 Effective Lumens