Color rendering is the ability of a light source to produce color in objects. The CRI is expressed on a scale from 0-100, where 100 is the best in producing vibrant color in objects. Relatively speaki [..]

A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (°K). Incandescent lights have a low color temperature (approximately 2800°K) [..]

Efficacy is an industry term for the amount of light produced per watt of electricity (comparable to efficiency). It is the rate at which a light bulb is able to convert electrical power (watts) into [..]

The term used to describe the total light which comes off a surface. Exitance is dependent upon the illuminance on and the reflectance of the surface.

The unit of measure for the density of light as it reaches a surface. One footcandle is equal to one lumen per square foot. Measured footcandles are sensitive to the distance from the source to the su [..]

The density of luminous flux on a surface, is measured in footcandles (one lumen per square foot) or lux (one lumen per square meter).

The result of the use of light.

The energy that allows us to see. Light can be expressed in terms of intensity (candela), flux (lumen), luminance (candela/square foot), and exitance (lumen/square foot).

Lighting power budget is the upper limit of power to be available to provide the lighting needs for a building, including all permanently connected lighting.

Lighting power density is the maximum allowable lighting density permitted by the code. It is expressed in watts per square foot for a given occupancy/space type.