The performance of any light fixture depends very
much on the light source (bulb) used. Different sources
produce different lighting effects, and many sources
have widely varying performance.
Lighting Measurement Terminology
The amount of electricity consumed by a light source.
The amount of light that a light source produces.
Lumens per watt.
The amount of light reaching a subject.
Today’s energy-efficient light bulbs, such as compact
fluorescent or LED, produce significantly higher
amounts of light for every watt of energy used. It is
most important to remember, however, that wattage
does not measure light output; it only measures the
electrical consumption of the bulb.
LED bulb by OSRAM SYLVANIA