What do we really know about light?

What do consumers know about lighting technologies? Or rather, what do they think they know? Do they know their watts from their kelvins and lumens? “What do they think about the biological effects of light?” asks LEDVANCE (a.k.a. Sylvania). UNESCO has declared May 16th as the International Day of Light, to bring global awareness to the importance of light and lighting technologies and educate the general public.

Many of us have chosen lighting products such as light bulbs and fixtures for our homes and offices only to find that the wrong product has been purchased. Do we actually know what was wrong with the product? Was it the fit, shape, size or color/light temperature? What is color light temperature, anyway? What is CRI and lumens and how do they affect my lighting choices? These are questions that are commonly heard in the lighting industry.

Changing from incandescent, fluorescent, HID and halogen light sources to LED is not only cost effective and better for the environment, but easier to understand when comparing color temperature and lumens. When a consumer sees Color Temperature or KELVIN, they may not understand what that offers. Color Temperature is the light color –Daylight/ White (5000-6500K), Cool White (3500-4500K, most common is 4000K) and Warm White (2300-3000K). The spectrum chart represents the Kelvin Temperature ranging from Pinkish-yellow colors to Blue-Purple, represented like a rainbow. Rarely do kelvin temperatures go lower than 2300K or higher than 6500K, only occasionally for industrial applications.

t is important in this current shift from incandescent, fluorescent, HID and halogen light sources to seek out corresponding equivalent watts and lumens in LED. Lower watts are represented in LED, like using 19W LED instead of a 75W incandescent. CRI is defined as “Color Rendering Index, (CRI) is 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. Light sources with a high CRI are desirable in color-critical applications such as neonatal care and art restoration.”

Lumens by universal definition are “The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source.” In simple terms, how much light is put out by a light source, i.e. LED, incandescent, fluorescent, HID in the application the consumer desires? The shape and size also matter, for example, one would use a Reflector style bulb in a down can fixture in the ceiling so the light from the bulb is not lost in the backside of the can, all the light is projected forward.

The size is also important to the application, for example, you wouldn’t use an R20 reflector in a 6” or 8” down can, the bulb would be lost up inside and very little light would escape through the tunnel to the intended location. Seek a lighting professional as often as possible when choosing the appropriate bulbs and fixtures.

Source Energy Star, LEDVANCE