LED Colour Temperature and CRI Explained


The colour temperature and CRI rating are important for understanding what type and quality of light is needed, so to ensure a successful lighting installation and meet the needs of the building’s occupants.

What you need to consider can be confusing depending on the requirements. So here are two key things to remember…

Colour Temperature

For the kind of mood or atmosphere you’d like to create for your space it’s all about the colour temperature of the lamp… the higher the colour temperature the cooler the impression of the white light.

Click on the chart to see how different light temperatures can be compared in our world and how lamps are classed into temperature Kelvin (K).


Colour Rendering Index

The Colour Rendering Index (CRI) is defined as the “Effect of an illuminant on the colour appearance of objects by conscious or subconscious comparison with their colour appearance under a reference illuminant.1

CRI is therefore a quantitative measure of the ability of a light source to reveal the colours of various objects faithfully in comparison with an ideal or natural light source, so making reds appear red and not pink.

Look at the colour differences of low and high CRI values as shown by iGuzzini in the images below:

iGuzzini LED Colour Rendering Index - cheap LEDs

iGuzzini LED Colour Rendering Index - high quality LEDs

In general light sources can be provided according to the required CRI value, such as:

CRI >95 for Exhibitions / Museums / Photography

CRI >90 for Food & Fashion

CRI >80 for Architecture & Offices

CRI >70 for Parking & Street Lighting

The CRI value should always be shown on the product data sheet to ensure you have the minimum value you require.

Through the invention of LED we are now able to have greater standardisation for unified colour temperature as well as improved colour clarity. When LED lighting has been installed in production assembly areas it is common to see a reduction in the number of defects of products produced, so ultimately leading to increased profit margins for the company.

Want to find out more then look to our LED Guide or contact us to help with your lighting upgrade or new installation.

  1. “CIE 17.4-1987 International Lighting Vocabulary”