22 February 2023
Understanding CRI and Colour Temperature

When it comes to lighting, two important factors to consider are the Colour Rendering Index (CRI) and Colour Temperature. CRI measures the accuracy of how colours appear under a specific light source, while Colour Temperature refers to the perceived warmth or coolness of light, measured in Kelvins (K). Both CRI and Colour Temperature play a significant role in both interior and exterior lighting and can have an impact on each other.

The Importance of Accurate Colour Rendering

CRI is a measure of how well a light source can render colours in comparison to natural light. It is measured on a scale from 0 to 100, with 100 being the most accurate. Lighting with a high CRI is important for tasks that require colour accuracy, such as in art galleries, museums, and retail spaces. In these applications, lighting with a high CRI allows colours to appear more vibrant, accurate, and natural.

When it comes to exterior lighting, CRI is equally important. High-CRI lighting can help to increase visibility and reduce the glare from car headlights or streetlights. For example, high CRI lighting in parking lots can improve visibility and make the area feel safer, making it easier to navigate and reducing the risk of accidents, while in supermarkets it can help showcase the freshness of the produce.

Creating the Right Atmosphere

Colour Temperature refers to the perceived warmth or coolness of light and is measured in Kelvins (K). Warmer colours have a lower Kelvin temperature (around 2,700-3,000K), while cooler colours have a higher Kelvin temperature (around 4,000-6,500K).

In interior lighting, the right Colour Temperature can create the desired mood and atmosphere for a space. For example, warm-coloured lighting can create a cozy and comfortable atmosphere in living rooms, bedrooms, and other relaxation spaces, while cooler-coloured lighting can create a brighter and more energizing atmosphere in workspaces, kitchens, and other areas where productivity is important.

When it comes to exterior lighting, the right Colour Temperature is also important. Cooler-coloured lighting can be effective for illuminating exterior spaces such as car parks, while warmer-coloured lighting can be more suitable for highlighting architectural features, providing a warm and inviting atmosphere.

How CRI and Colour Temperature can affect each other

CRI and Colour Temperature are closely related and can have an impact on each other. For example, high CRI lighting can often appear warmer in colour temperature, as it contains more red and yellow light. Conversely, cooler light sources tend to have a lower CRI, as they may not accurately render certain colours.

When selecting lighting for your space, it is important to consider the interplay between CRI and Colour Temperature. A high CRI may be desired for its colour accuracy, but if the lighting temperature is too cool, it may create an unwelcoming or sterile atmosphere. On the other hand, warm-coloured lighting may create a comfortable atmosphere, but if the CRI is too low, it may not accurately render colours and artwork in a museum or gallery.

At the Strawberry House, the LED strip in Flat Freddie 14 used has a CRI value of 95+ and a 2700K colour temperature which was specifically chosen to highlight and bring out the red tones from the timber.

View Project

For the Mercedes-Benz Facility in Alexandria, a colour temperature of 6500K was chosen with a high CRI of ≥90, to comply with exacting demands for colour matching of metallic paint finishes. Additionally, this choice of colour temperature throughout the building lends a crisp, daylight appearance.

View Project

In BEGA’s BugSaver exterior luminaires, Amber (similar to 1800 Kelvin) is used during low activity hoursThis targeted control of colour temperature during night-time hours ensures minimal impact on the biosphere of light-sensitive insects while ensuring that the safety of passers-by will not be infringed upon

Learn More about BugSaver

E-Line Next by Trilux

E-Line Next by Trilux

THE CHALLENGE LED continuous line systems have enormous potential, e.g. in industry, retail, office and education. ...
LC Connect & WTEC

LC Connect & WTEC

CONNECTED LIGHTING SOLUTIONS There are increasing demands on spaces and the businesses that run them, to be more ...
Panzeri – Hilow

Panzeri – Hilow

HILOW: THE CLOUDS OF CUSTOMISABLE LIGHTSCREATED BY MATTEO THUN Panzeri was founded in the late 1940s by Carlo ...


At Light Culture we are inspired by sustainable
lighting solutions. We are committed to protecting
the environment and preserving resources.