What is lumen per square metre?
Lumen per square metre is a unit of illuminance numerically equivalent to lux. It expresses the amount of light falling on a surface and is used in lighting engineering and photometry to quantify light intensity at a specific location.
What is foot-candle?
A foot-candle is an imperial illuminance unit equal to one lumen per square foot. It is used in the United States for stage and event lighting specifications, photographic exposure references, and building lighting compliance standards.