Use the Color Rendering Index (CRI) to Select Perfect LED Lights for Your Application
The light bulb is considered one of the most important inventions. Second, only to the human ability to make fire, the light bulb helped to continue daily life after sundown. Humans could socialize, travel, and work safely into the night with artificial light. The original light bulb designed by Thomas Edison in 1879 produced a more consistent, longer-lasting, higher-quality light than oil or gas lamps. However, it was one-dimensional.
Fast forward to today, thanks to LED lighting technology, LED light bulbs are available in a wide range of color temperatures with a high color rendering index rating (CRI). By understanding the color rending index and color temperatures, you can select an LED light that works for your application, from creating a warm, cozy atmosphere to a bright work environment – and everything in between.
Lord Kelvin, Color Temperature, and LED Lights
Let’s go back to 1848 when William Thomson, aka Lord Kelvin, saw the need for a temperature scale where absolute zero was the scale’s null point, which we know as the kelvin scale. The Kelvin scale is the International System of Units (SI) chosen scale to measure thermodynamic temperature.
So, what does all of this have to do with my LED lights?
Every object, lightbulbs included, that has a temperature emits electromagnetic radiation (don’t worry, it’s not the bad kind). Thermodynamic temperature measures the energy of an object. Think about the last time you saw a thermal imaging camera in action – perhaps during a building inspection or watching a ghost hunting show. That camera shows the apparent surface temperature, via the radiation emitted, of the object being measured. The hotter something is, the more intense and broader the radiation becomes and the higher the light frequencies it emits. At about 800 kelvin, we see the light as a dull red glow. Around 3000k, the light becomes orange; by 6000k, the light is bright white; between 9000 – 10000k, we see the light as blue.
Why Does Color Temperature Matter?
The color temperature of the LED lighting you use will significantly impact the atmosphere or mood of your space. Lower-temperature LED lights in the 2000 – 3000k range create a warm, welcoming glow. They are often used in homes, hotels, and restaurants for ambient lighting. LED lights, like the EarthTronics LED Color Selectable Disk Light, allow you to select the color temperature to fine-tune the lighting to your needs.
Bright white LED lighting in the 4000k range is used in manufacturing, warehouses, and other spaces that require precision work. You’ll also want to use high-temperature in parking lots and areas where safety is a concern.
A good rule of thumb is that bright white daylight – high noon on a sunny day – is 5000k. Go lower if you want room lighting to feel more like candlelight or sunset. If you want a bright, well-lit space that keeps people alert, go higher.
Understanding the Color Rendering Index (CRI)
Now that you’ve got the color temperature down, you can see how color temperature can significantly affect your lighting. But there is another light bulb value that you can use to create the right light impression.
The Color Rendering Index, written as CRI, of a light bulb is a measurement of how well the light source shows the color of an object. The CRI is a scale from 1 – 100 and measures how well the artificial light source compares to sunlight, with 100 being the closest to natural light. CRI values of 90 and above are considered excellent, while scores below 80 are generally regarded as poor.
It’s important to note that CRI is entirely different from color temperature. For example, you can have two LED light bulbs that are 3000k, but objects under each light look very different. Have you ever purchased an item of clothing in a store, only to get home, and under the lights in your bedroom, the garment’s color looks entirely different? That’s CRI at work.
A quick refresher on how color works helps explain this. Sir Isaac Newton discovered that color was not inherent in an object but that the surface of objects reflected some colors and absorbed all others. The human eye sees only the reflected colors. Newton also discovered that the white light produced by the sun separated into the colors of the rainbow when it passed through a prism. When white light strikes a white object, it appears white to us because it absorbs no color and reflects all colors equally. When it hits a colored object, this color light is reflected back. A black object absorbs all colors equally and reflects none, so it looks black to us. Scientists estimate that the human eye can see about one million shades of color.
Using the CRI and Kelvin Scale to Select LED Lighting
LED lights with a high CRI show better color and help fine details, like texture, stand out. High CRI LED lighting is essential in applications where visual accuracy is required. This includes retail and grocery stores, schools, universities, healthcare, and manufacturing settings. High CRI lighting also has applications in the home and office. Mimicking natural light indoors has numerous health benefits. As builders and designers incorporate human-centric design – where the lighting in a space is designed to mimic natural light – CRI becomes increasingly essential.
EarthTronics recessed downlight with a CRI of 90+, and 3000k temperature is used in several spaces to create a high-color rendering and a bright white light. An LED A-Bulb is used in standard light fixtures to gain the advantage of an 80+ CRI rating with a lower color temperature to create a warmer environment without sacrificing color quality.
Now that you understand the value of the Color Rendering Index and the color temperature scale, you can use this information to your advantage to create the perfect lighting for specific areas. One of the many benefits of LED lighting technology is the wide range of options for both color temperature and CRI – and in many instances, the ability to set the color temperature to your liking.
EarthTronics LED Lighting
EarthTronics manufactures an extensive line of LED lighting fixtures and LED lamps that provide a positive economic and environmental impact for our clients. Whether for a new build or retrofitting existing lighting, we focus on creating durable LED products that are installation ready. We’d love to chat with you about your next lighting project and how EarthTronics makes it easier and most cost-effective to use LED technology.