BY I.M. LYTEMAN
If you aren’t an engineer or a trained lighting designer, some of the terms that are casually bandied about the LED business can be confusing. Here’s a basic lighting library for some of the more common measurements, acronyms and product types:
BEAM ANGLE – The angle between the two planes of light where the intensity is at least 50% of the maximum intensity at the center of the beam. This helps measure where light is focused.
BINNING – A way of sorting LEDs so that they have a similar light output. Binning helps limit variances in color temperature, creating a consistent look. Premium LED products will often be grouped – or “binned” — within two steps in a MacAdam ellipse.
CCT – Short for Correlated Color Temperature, a means of recording the color or warmth of white light measured in degrees Kelvin by its proximity to the chromaticity coordinates at the black body locus. A lower CCT indicates a “warmer” color temperature such as red or orange while a higher CCT indicates a “cooler” color temperature.
CRI – Short for Color Rendering Index, a method for measuring how well a given light source shows colors in the objects it illuminates. The higher the CRI, the more accurately color is seen. A typical LED will have a CRI around 80. A quality LED will measure 90+.
DMX – An acronym for Digital Multiplex, it is overwhelmingly used to refer to industry standard communications for programming and controlling lighting sequences and effects.
DRIVER – A device that converts power from AC to DC and regulates the voltage or current levels required for LED fixtures.
FOOT-CANDLE – A unit of illuminance equal to one lumen per square foot, used to measure the amount of light in a given area.
HEAT SINKING – A process that utilizes thermally conductive materials to draw heat away from an LED. Good heat sinking will diffuse heat from an LED, making it safer and more efficient while extending the life of an LED lighting fixture.
IK rating – An impact rating, from 0-10 that measures an electrical fixture’s degree of protection from external impact, measured in joules, where IK00 is essentially unprotected and IK10 withstands an impact up to 20 joules.
IP rating – An Ingress Protection rating, where the first number indicates protection from dust and solid particles (on a scale of 0-6) and the second number indicates protection from fluids (on a scale of 0-8). IP00 would represent no protection, while IP68 would represent a dust-tight fixture (6) as well as a fixture able to withstand continuous immersion (8).
KELVIN – The standard unit measure of the color temperature of light, on a scale from 1,000 to 10,000. Kelvin can be confusing at first because “cooler” temperatures of white light measure higher on the Kelvin scale, while “warmer” white color temperatures measure lower.
LUMENS – The luminous flux, or measured brightness, of light output in a fixture. Simply put, the more lumens, the brighter the light.
LUMENS PER WATT – A measure of lighting efficiency that tells how many lumens you observe per Watt of power used. Because LEDs emit more lumens while consuming considerably less power than traditional light sources, they have a higher ratio of lumens per Watt. (Which means they conserve energy!)
LUMINANCE – The light within a given area.
LUX – A unit of illuminance equal to one lumen per square meter, also used to measure the amount of light in a given area.
MacADAM ELLIPSE – A measure of color consistency charted on a chromaticity graph. The MacAdam ellipse shows how colors within a certain grouping are identical to the naked human eye.
RGB (and COLOR CHANGING) – RGB simply stands for the three primary colors: red, blue and green. Premium RGB or color changing LEDs can be used to create more than 16 million custom colors. RGBW includes a White LED in the mix; RGBA includes an Amber LED. Lighting designers use DMX controls to program these LED systems.
STATIC WHITE and STATIC COLOR – Continuously powered, constant white or colored light. Because LEDs work with constant current, they consume less energy – and they don’t flicker.
WATTAGE – The amount of electrical power required for a lighting fixture to function.