What does the 'lumen' value marked on the LED lamp mean?
Lumen = unit of luminous flux.
Lumen is one of the most important criteria for comparing lamps with each other.
The luminous flux is a measure of the total amount of visible radiation that is emitted per second. The human eye catches certain wavelengths (colors) better than others. For example, we see green and yellow much better than ultraviolet and infrared. Lumen is a good comparative factor, because with the same wattage there can be a big difference in the perception of different shades. So look for an optimal combination of 'lumens per watt'.
