Frequently Used Words

FREQUENTLY USED WORDS

Some of the words you find on our site are obvious, and some, not so much. That's why we've created a handy glossary to clarify the more challenging terminology. Mesopic lumens anyone?

LIGHT EMITTING DIODE

A diode of a semiconductor material, emitting light when a forward bias is applied.

COMPACT FLUORESCENT LAMP (CFL's)

First generation of energy-saving light bulbs, which last longer and use less energy than traditional light bulbs for the same level of intensity- they contain mercury -- which is a big problem. LED's save more energy, are less wasteful, and are not toxic to dispose of -- not to mention last up to 10 times longer.

METAL HALIDE LAMP

Electric lamp that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides (compounds of metals with bromine and iodine).

LIGHT OUTPUT

How much light a light source will generate. Light output is measured in lumens at the light source.

COLOR RENDERING INDEX

A quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source.

COLOR TEMPERATURE

The temperature at which a black body would emit radiation of the same color as a given object.

MESOPIC VISION

The combination of photopic and scotopic vision in low but not dark lighting situations. What's photopic and scotopic? Look below!

SCOTOPIC VISION

Relating to or denoting vision in dim light, believed to involve chiefly the rods of the retina.

PHOTOPIC VISION

The vision of the eye under well-lit conditions. In humans and many other animals, photopic vision allows color perception, mediated by cone cells, and a significantly higher visual acuity and temporal resolution than available with scotopic vision.

PHOTOPIC LUMEN

A type of light measured in lumens generally detected by common light meters and accounts for part of the human eye’s perception of brightness or light levels.

PHOSPHORS

Substance that exhibits the phenomenon of luminescence.

S/P RATIO

The ratio of scotopic to photopic lumens produced by a light source. An appropriate S/P ratio will offer a more comfortable atmosphere and better perceived brightness.

LUMINAIRE

Complete lighting unit.

LIFE CYCLE ANALYTICS

A tool that helps companies to understand the environmental impacts associated with their products, processes, and activities.

CORPORATE SOCIAL RESPONSIBILITY

Corporate initiative to assess and take responsibility for the company’s effects on the environment and impact on social welfare.