California IDEX Practice Exam

The measurement and description of the brightness of a direct glare source is best represented by "footlambert." Footlamberts quantify luminance, which correlates to the brightness perceived from a given light source. Specifically, they measure the intensity of light that reflects off a surface and is perceived by the human eye, making this unit particularly relevant for discussing glare and brightness in visual environments. While candelas per square meter also measure luminance, footlamberts are more commonly associated with the context of glare and visual comfort in the field of lighting. Footcandles measure illuminance, referring to the amount of light hitting a surface, and lumens quantify total light output, rather than perceived brightness. Thus, footlamberts are the most accurate choice for describing direct glare sources.