Exploring Color Temperature and Rendering


Not all light bulbs and fixtures are created equally. The interplay of wattage, colour and temperature can have a profound impact on how a finished space looks and feels. That’s why you should always consider some key elementswhen choosing the bulbs and fixtures for the room you are designing.

Whether the room has lots of natural light, or you are relying on artificial light sources, the colour and mood in a room can drastically change depending on that source of light. This is when the knowledge of colour temperature and colour rendering, becomes key in achieving your desired look and feel. In this article, we’ll bediscussing these two important aspects of lighting to help you decide the right lighting fixture for your residential or commercial space.

Colour temperature or correlated colour temperature (CCT)

When it comes to deciding on the right light fixtures for your space, there are some key aspects we should keep in mind, including energy efficiency, price, functionality, and style. 

While undoubtedly,the factors listed below are all essential factors to consider, we rarely talk about the light itself and even less – about its colours and desired effect on our room and space. If you’re looking to create your ideal cosy space, then this is where a knowledge of colour temperature or CCT comes in handy.

Colour temperature is a numerical value given to characterise different colours of light, measured in Kelvin (K). In other words, colour temperature measures the degree of warmth (yellowness) or coolness (blueness) of a light source, scaled from 1000 to 10,000. 

Colour temperature typically has three standard ranges: Warm White (ranges from 2700K-3000K), Cool White (ranges from 3000K-5000K) and daylight (ranges from 5000K-6500K). 

Below we’ve listed the common ranges of colour temperature in lights sources –

Soft white: This warm light source sits in the lower temperatures at 2700K-3000K. By emitting a cosy warm glow, this temperature is perfect for living areas and bedrooms.

Bright white or blue-white: With a colour temperature of 300K-4000K, these lights are even warmer with more yellowish-white tones and ideal for more active areas such as hallways or kitchens.

Bright White Bright white is between white and blue tones, with the temperature in between 4000K-5000K, great in cupboards or areas of the house that don’t recvice a lot of natural light.

Daylight: With 5000K-6500K, it has a more bluish tone with maximised contrast for colours, ideal for a commercial and industrial setting. 

Importance of colour temperature in light sources

As explained above, colour temperature in light sources is a measurement of the warmness or coolness of a light source. As humans, we pick up on subtle changes in our environment and can experience mood changes because of them. Soft white lights make us feel relaxed while brighter blueish tones sharpen focus and productivity. Studies believe that this is due to our Circadian Rhythm.  Our circadian rhythm is a 24-hour day-night cycle that primarily governs different psychological processes of living beings, including the sleep-wake patterns.

A recent investigation also found a correlation between colour temperatures of light sources and the heart rate variability. The heart rate variability in different periods of our daily life varies, and the power spectrums of the heart rate under warmer or cooler colour temperature fluctuate. When the colour temperature is in between 5000k-6.500k, the heart rate increases significantly. Lights with low temperature (2700k-3000k) on the other hand, keep the heart rate stable.

If you want people to feel a certain way when settling down in a room, it goes without saying that the right light temperature is key to creating an ideal environment. 

Colour Rendering Index (CRI)

When it comes to buying and installing lighting fixtures in your residence, workplace or commercial space, colour rendering index is anotheressential aspect to consider.

In the lighting industry, Colour Rendering Index (CRI) is a universal criterion for distinguishing between the brightness, pigmentations and saturation of object colours under given lighting.

CRI is the specific measurement of a light source’s ability to show or “render” an object’s colour. CRI,along with the colour temperature,is used to create “natural” or artificial lighting in spaces, by focusing on the objects themselves.

How is the Colour Rendering Index measured?

This index is measuered on a scale between 0 to 100. At 0, colours will blend in and appear muddy o while at 100-  colours are easily distinguished. When lighting a space, using a higher CRI value, results incolour quality. Another way to look at the index is to consider 100% closer to a natural light source or daylight.

Here’s an instance of how you can measure the CRI of your light bulb. Take a black and a dark blue object and place them under your light source, if you can’t see any visible colour different, then this light source has a lower CRI.

Why CRI is so important when evaluating lights?

CRI plays a vital role in ensuring your space displays colours, allowing you to show off your vibrant décor, to display products or even match your wall colour to the original paint swatch.  Without it, your area will only translate into a flat, dullpresentation whenever illuminated.

What are the correlations between LED lights and CRI?

Different types of lights have different colour-rendering abilities that might not match your needs. Most of the incandescent or fluorescent lights only have a CRI range of 24 to 85 at the most. Out of all the available lighting fixtures, LED lighting solutions provide a higher CRI, rendering colours more accurately. 

In modern LED’s the CRI can reach as high as in the 90s,resulting inperfect colours for your living space or professional settings where colour matching is crucial. Think textile factories or printing facilities!

With the continual progression and innovation in LED technology, these fixtures and their performance are better than ever acting as an affordable solution for any lighting problem.