Guide to light sources
Basic definitions
Lumen
Unit of measure of the luminous flux.
Lux
Unit of measure of illuminance, lumen per square meter.
Watt
Expresses the quantity of energy (power) absorbed.
Lumen/Watt
Expresses the efficiency of the light source: how many lumens per watt.
Colour Temperature (expressed in degrees Kelvin)
Very Warm: < 2700 K
Warm White: 2700 – 3000 K
Cold (Natural) White: 3000 – 4000 K
Very Cold: > 4000 K
Cold (Natural) White: 3000 – 4000 K
Very Cold: > 4000 K
