When we start to explore the world of outdoor lighting there are a lot of factors involved in the ultimate end result. You want your outdoor lighting to illuminate your setting for ambiance and also for security. Designing lighting to achieve aesthetic goals can be a tricky process. You want your setting to create a mood without being too obtrusive. You want to see the light, but not concentrate on the fixture.
In order to properly illuminate your setting one of the tools we use is the Color Rendering Index, also called CRI. The CRI is a scale used to measure the ability of a light source to reproduce the colors of various objects faithfully in comparison to an ideal or natural light source. In layman’s terms this means how true to life these colors appear when they are being illuminated with anything other than natural light.
Every lighting source can be measured using the CRI. The CRI only measures the visible quality of light. Every type of light source generates a color, and the quality of light depends on how well the light reflects the truest color of an object. Photographers, for example, use the CRI when choosing light sources to light their images. The peak of CRI is 100. Poor colors range from 79 and below. Good color is achieved from 80-94 on the CRI and anything 95 or higher is considered to be great color.
Nowadays, we are all acutely aware of energy efficiency when we choose lights. A good many bulbs which rate high in energy efficiency also have a high CRI. Quartz halogen bulbs are a wonderfully efficient light source which have a long life as well. Quartz halogens have a life of 2,000 – 4,000 hours. These halogens also have a perfect CRI of 100. They are most commonly used in the automotive industry as well as commercial lighting and residential indoor and outdoor lighting scenarios.
Another bulb that has a nearly perfect CRI of 96 is the ceramic metal halide. It also has a very long life of 12,000 – 20,000 hours. Ceramic halides are generally used in residential as well as commercial settings. These lights are quite appealing for the longevity factor as well as their ability to illuminate objects in a true light. Imagine not having to replace a bulb for 3-5 years!
Ceramic metal halides are another great bulb with a life of 12,000 – 20,000 hours. These are also used in commercial and residential settings. The CRI of a metal halide is an 80 +. Last but certainly not least are the LED’s. LED is hailed for it’s “green” factor. LED’s have a life of 25,000 – 50,000 hours. They also cost one tenth the price to burn in comparison to your other bulbs. Unfortunately, at the present time the LED has a CRI of 50. All is not lost though, LED technology is moving in leaps and bounds and the technology is leaning towards having better “true to life” quality. In the near future many believe the light quality will soon catch up with the others in terms of warmer true-to-life tones. Here at Outdoor Lighting Perspectives San Antonio we are carefully watching the LED technology become mainstream and with that the CRI is predicted to improve tremendously.