Importance of CRI in LED

LEDs are made as a flat sheet, often called a wafer. These are separated into smaller chips and grouped together based on the three characteristics; the CRI, color temperature and lumen output. In here, we will talk about the importance of CRI (Color Rendering Index) in LED lights

 

What is Color Rendering Index?
The CRI is considered the most effective way of measuring the color characteristics of a light source. In common terms, CRI is a measurement of a light source's capability to display the colors of an object naturally or realistically as compared to a typical light source, either incandescent light or sunlight.

 

Importance of CRI in LEDCRI is calculated from the variations in the chromaticities of eight CIE standard color samples. When illuminated by a source of light and by a reference illuminant of the same correlated color temperature (CCT); the smaller the average variation in chromaticities, then the CRI is higher. A CRI of 100 is the highest value. Halogen contains a CRI of 100. Those lower CRI values suggest that some colors may not look natural when lighted by a lamp. The incandescent lights contain a CRI that is over 95. Cool white fluorescent lights have a 62 CRI. But those fluorescent lamps that contain rare-earth phosphors come with CRI values of more than 80.

 

For CCTs that are lower than 5000 K, the light source used in the calculation process of CRI would be the SPDs of the blackbody radiators. On the other hand, imaginary SPDs calculated from a mathematical model of daylight are used for CCTs that are over 5000 K. These sources of reference were chosen to respectively estimate incandescent lamps and daylight.

 

Defining the Color Rendering Properties of the Sources of Light
Color rendering is a basic term that is used to describe the capability of a source of light to give the information of color to an observer whenever an object is illuminated by that particular source. The color rendering properties of a light source will not Importance of CRI in LEDbe able to be examined accurately through visual assessment, or by using a quick evaluation of its SPD (spectral power distribution). Instead, a correct calculation process should be used.

 

The Color Rendering Index (CRI) is now the only color rendering measurement that is acknowledged worldwide, and is utilized by the lighting industry globally. Having said that, several other procedures for measuring the color rendering properties of electric powered light sources. These procedures have limits in defining the different parts of color perception that is associated with color description. For example, the naturalness, sharpness and discriminability. Every procedure uses the SPD of the source of light. The majority of them include more than one reference light source which is compared by a certain source of light. Most processes also use colored items as a set reference to be illuminated.

 

To conclude, the higher the color rendering index, the better its color rendering capability. Fluorescent lights are considered quite poor in CRI as they have a score of 70. A CRI index that is higher than 80 is considered to be an ideal lighting solution. For that reason, LED downlights and other LED bulbs are the best replacements for incandescent bulbs, considering that most LEDs have a CRI above 80.