What is the “CRI” (Color Rendering Index) and what does it mean for portable lighting?

Lighting terminology can be confusing, from measuring light output with Lumen, Lux and Candela, to measuring the color of the light with CRI and Kelvin. A lot of these measurements are used in conjunction with each other but are not correlated. For example, you can have a 2,000 lumen light with extremely high candela (if the beam is focused) or the same 2,000 lumen light source with extremely low candela (if it has a flood pattern). 

To lay down a foundation, it is helpful to separate the Color Rendering Index from the Kelvin Temperature Scale. Kelvin is frequently used by light “bulb” manufacturers to clarify the temperature of the light to the consumer. They will have measurements like 2,700k (Kelvin) or 5,000k, indicating the temperature of the light. For reference, the temperature of candlelight is 2,200k and typical florescent lighting in an office building is about 4,500k. 

Kelvin is the temperature color of the light itself and CRI is how well an artificial light will reproduce colors. These two light measurements are independent from one another, and you cannot mathematically predict CRI from Kelvin or Kelvin from CRI. Knowing that the two measurements are separate, let us focus on CRI. 

Knowing that the Color Rendering Index shows how well artificial light will reproduce colors, let us get into the index. The index is a scale from 0 to 100, with 100 (percent) being the way objects appear in natural daylight and 0 being all colors look the same. The lower the CRI, the more distorted, washed out or similar the different colors become. Candlelight measures around 83 CRI, which brings up a great point, that a warmer color is not always a higher CRI. Candlelight is “warm” but is lacking purple and blue, therefore does not allow all colors to be seen. Fluorescent office lights are around 60 and lack orange and red. Most of Streamlight’s handheld lights are around 80 CRI, which will give you a bright white light, but some colors will not be accurately represented. That typically does not become an issue unless you are cutting open a steak to see the temperature, matching automobile paint, putting on makeup, following a blood trail or if you need to “cut a specific color wire”. 

Streamlight's Color-Rite Technology^® produces flashlights that are 90+ on the Color Rendering Index, which will have an excellent representation of color. We have put these high CRI LEDs in many automotive lights over the years and now have integrated them into our Stinger^® platform, with the Stinger^® Color-Rite^®. When your application demands accurate representation of colors, Color-Rite Technology^® by Streamlight is the right choice.