Color rendering index (CRI): Measure of the degree of color shift an object undergoes when illuminated by a light source as compared to a reference source of the same color temperature. CRI is expressed on a scale of 0-100, with a higher value representing less color distortion, or a more “accurate” color. Natural daylight is rated 100.
Correlated color temperature (CCT): Is the measure used to describe the relative color appearance of a white light source. CCT indicates whether a light source appears more yellow/gold/orange or more blue, in terms of the range of available shades of "white." CCT is given in kelvins (unit of absolute temperature).
Compact fluorescent lighting (CFL): A type of fluorescent lamp. Many CFLs are designed to replace incandescent lighting and can fit in existing light fixtures formerly used for incandescent bulbs. Compared to general service incandescent lamps giving the same amount of visible light, CFLs consume less power and last longer.
Color rendering index (CRI): Indicates how well a light source renders colors of people and objects, compared to a reference source.
Efficacy: Is the most commonly used measure of the energy efficiency of a light source. It is stated in lumens per watt (lm/W), indicating the amount of light a light source produces for each watt of electricity consumed; The higher the number, the more efficient the bulb.
Incandescent lighting: Light produced when a filament is heated to incandescence using an electric current (e.g., light bulb). Incandescent lighting is very inefficient, turning much of its energy into heat rather than light, and is gradually being replaced in many applications by LEDs and other devices.
LED: LEDs are based on inorganic (non-carbon based) materials. An LED is a semi-conducting device that produces light when an electrical current flows through it. LEDs were first developed in the 1960s but were used only in indicator applications until recently.
Light source: Any device serving as a source of illumination.
Lumen: A unit of measurement that expresses the total quantity of light given off by a source, regardless of direction. One lumen is equal to the amount of light that one candle emits over one square foot of surface that is exactly one foot away from the flame; the amount of light a bulb produces. This is “brightness” or “light output.” Your reference point: A standard 100-watt incandescent produces about 1,700 lumens.
RGB: Stands for red, green, and blue, the three primary colors of light. When the primaries are mixed, the resulting light appears white to the human eye. Mixing the light from red, green, and blue LEDs is one way to produce white light.
Solid-state lighting (SSL): Technology uses semi-conducting materials to convert electricity into light. SSL is an umbrella term encompassing both light-emitting diodes (LEDs) and organic light emitting diodes (OLEDs).
Volt: A unit of measurement for electric potential and electromotive force.
Watt: Not a measure of brightness; instead, it’s a measure of how much energy a bulb consumes to reach its claimed brightness; a unit of measurement for power equal to one joule of energy per second.
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