What is the basic measure of the amount of light produced by a light source called?

The basic measure of the amount of light produced by a light source is known as a lumen. This unit quantifies the total quantity of visible light emitted by a source in all directions. The concept of lumens is essential in lighting design, as it allows for comparisons between different light sources in terms of their brightness. Understanding lumens helps consumers and professionals select appropriate lighting for various applications, ensuring optimal illumination for tasks or environments.

Footcandles and lux are both units that measure illuminance, which refers to the amount of light that falls on a surface area, rather than the amount of light produced by a source. Footcandles are commonly used in non-metric countries and specify illumination per square foot, while lux measures illumination per square meter. Watt, on the other hand, is a measure of power consumption, not light output. Thus, while these other terms are related to light, they focus on different aspects of lighting rather than directly measuring the light emitted by a source.