# Illumination Converter

Illumination, in the context of lighting and optics, refers to the amount of light falling on a surface per unit area. It plays a crucial role in various fields such as photography, architecture, and engineering.

To accurately measure and understand illumination, various units are employed. In this article, we will explore the key illumination units and their conversion factors to simplify the conversion process.

• Lux (lx): Lux is the unit of Illuminance in the International System of Units (SI), measuring lumens per square meter (lm/m²), or the illumination produced by luminous flux of one lumen falling perpendicularly on a surface of one square meter.
Conversion Factor: 1 lx = 1 lm/m²

• Meter-candle (m•c): An older unit of illumination, equivalent to lumen per square meter.
Conversion Factor: 1 m•c = 1 lm/m² = 1 lx

• Centimeter-candle (cm•c): Similar to meter-candle, centimeter-candle is an older unit of illuminance, equivalent to lumen per square centimeter.
Conversion Factor: 1 cm•c = 1 lm/cm² = 10000 lx

• Foot-candle (f•c): Foot-candle is also an older non-SI unit, representing lumen per square foot.
Conversion Factor: 1 f•c = 1 lm/ft² = 10.764 lx

• Flame (flame): Flame is a unit used in photometry to measure the intensity of light from a candle. One flame is equivalent to 4 lumens per square foot. Conversion Factor: 1 flame = 4 lm/ft² = 43.056 lx

• Phot (ph): Phot measures illuminance in terms of the luminous flux incident on a surface. One phot is equivalent to one centimeter-candle and is equal to 10 kilolux.
Conversion Factor: 1 ph = 10000 lx

• Nox (nx): Nox is a unit of illuminance used to measure low illumination (dark night) and is equal to one millilux.
Conversion Factor: 1 nx = 0.001 lx

• Lumen per square meter (lm/m²): The illumination produced by luminous flux of one lumen falling perpendicularly on a surface of one square meter.
Conversion Factor: 1 lm/m² = 1 lx

• Lumen per square centimeter (lm/cm²): The illumination produced by luminous flux of one lumen falling perpendicularly on a surface of one square centimeter.
Conversion Factor: 1 lm/cm² = 10000 lx

• Lumen per square foot (lm/ft²): The illumination produced by luminous flux of one lumen falling perpendicularly on a surface of one square foot, commonly used in the United States.
Conversion Factor: 1 lm/ft² = 10.764 lx

• Watt per square centimeter (W/cm²): Watt per square centimeter measures the power per unit area, providing information on energy concentration. The conversion between illuminance (lux) and irradiance (W/cm²) depends on the spectral distribution of the light source. The conversion factor of 1 watt at a wavelength of 555 nm is equal to 683 lumen.
Conversion Factor: 1 W/cm² (at 555nm) = 683 lm/cm²

Understanding the various illumination units and having a convenient conversion tool can greatly assist professionals and enthusiasts in fields where precise control and measurement of light are essential. Whether you are an architect, photographer, or engineer, a solid grasp of illumination units is crucial for achieving optimal results in your work.