The world of lighting has evolved significantly with the advent of LED technology, and two key specifications now play a crucial role in choosing the right light source for a particular application: the Correlated Color Temperature (CCT) and the Color Rendering Index (CRI). These terms describe different aspects of the output of a light source, and both use the word "color" in their names, making them important to consider when selecting LED lighting.

Warm and Cool Light: Understanding Color Temperature

The visible light spectrum of colors, from red to violet, can also be described by color temperature, measured on the Kelvin (K) scale. This is where CCT comes in - it refers to the color of the light itself. However, the "T" in CCT doesn't refer to the actual temperature of the light source. Instead, it represents the Kelvin temperature of a black body radiator. Simply put, a black body is an object that can be heated to produce light. If you heat a piece of steel to 2700 degrees Kelvin and compare it to a light source with a CCT of 2700 degrees K, they will both emit the same color. This concept is based on physics, but it's a practical way of assigning a numerical value to the color of light.

Thanks to LED manufacturing processes and technology, various color temperatures are available, ranging from 2700 degrees K for warm incandescent tones, 3000 degrees K for halogen-like hues, 4000 degrees K for moonlight, to 5500 degrees K for a cooler, bluish white light.

Color Rendering Index: Revealing True Colors

The Color Rendering Index, on the other hand, is a quantitative measure of a light source's ability to accurately reveal the colors of various objects compared to a natural light source. A high CRI, reaching up to a maximum of 100, means that the light source has the same color-rendering capacity as natural daylight. LED lighting with a CRI of 80 or higher is typically used in color-critical applications such as art galleries and merchandising. The lower the CRI, the more distorted the color rendering becomes, with negative CRI values indicating extremely poor light sources that alter color perception. Some LED manufacturers claim to have achieved CRI values of up to 98.

In conclusion, understanding the difference between CCT and CRI is essential for choosing the right LED light source for your needs. While CCT refers to the color of the light itself, CRI measures the ability of the light source to reveal the true colors of objects.

(Pics sourced from internet)

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