Lumen is a unit of luminous flux, a measure of the total quantity of visible light emitted by a source per unit of time. It is a fundamental concept in the field of lighting design and illumination engineering. One lumen is defined as the luminous flux emitted into a solid angle of one steradian by a point source with a uniform luminous intensity of one candela. In practical terms, lumens indicate the total amount of light output from a light source, such as a lamp or a light fixture, in all directions. The higher the lumen rating, the brighter the light source. Lumens are used to quantify the brightness of various light sources, including incandescent bulbs, fluorescent tubes, LED lights, and natural daylight. Lighting designers and engineers use lumens to calculate the required number and placement of light fixtures to achieve desired illumination levels in a space, considering factors such as room size, surface reflectance, and task requirements. The concept of lumens is essential for creating effective and efficient lighting solutions in a wide range of applications, from residential and commercial interiors to outdoor spaces and architectural lighting.
lighting, illumination, brightness, light output, luminous flux, visible light, light source, candela, steradian
CITATION : "John Armstrong. 'Lumen.' Design+Encyclopedia. https://design-encyclopedia.com/?E=432481 (Accessed on July 09, 2025)"
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