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The Science of Illuminance
The Science of Illuminance
Illuminance is the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface, wavelength-weighted by the luminosity function to correlate with human brightness perception.
Introduction & History
The study of photometry, which includes illuminance, began in the 18th century. The development of standard light sources and photometers allowed for precise measurement. The unit Lux is derived from the Candela, the SI base unit of luminous intensity.
Key Units
Lux (lx)
The SI unit of illuminance, equal to one lumen per square meter.
Foot-candle (fc)
An imperial unit of illuminance, equal to one lumen per square foot.
Practical Applications
Lighting Design for Architecture
Photography and Cinematography
Horticulture (Grow Lights)
Occupational Health and Safety