Lighting Design - Colour Temperature

Why is lighting important in office interior design?

People in general spend about seven to ten hours a day, five days a week in an office. This rounds to about 40 hours a week, close to one-third of a person’s lifetime. In the workplace of today, where the majority of information is processed visually, lighting plays a vital role in the design of the office space. In this blog post we will delve deeper into colour temperatures, what they mean in the lighting design industry, and how they can be chosen for a space.

What is Colour temperature?

The colour of light used is a matter of significance in lighting design for an office. Although white is used as a blanket term for most hues used for lighting a commercial or residential space, there are various segments differentiated by colour temperature. The colour temperature denoted in Kelvins signify the temperature of an ideal black-body radiator emitting light when heated. The tone of light emitted by this radiator varies upon its temperature and will appear redder at lower temperatures and bluer at higher temperatures.
Although this is the underlying principle, for ease of computation, the more commonly used parameter is CORRELATED COLOUR TEMPERATURE (CCT). The CCT scale ranges from 0K to over 15,000K. The most notable temperatures are as follows:
• Candle lights – 1,800K
• Warm white light – Between 2,000K & 3,000K
• Soft white light – Between 3,000K & 4,000K
• Neutral white light – Between 4,000K & 5,000K
• Daylight – Between 5,000K & 6,000K
• Cool white light – Between 6,000K & 7,000K
• Clear blue sky – 10,000K and above
Of these, although various different warmer and cooler options are available for the following light technologies, normal incandescents fall at about 2,800K, the common fluorescent tubes fall at about 4,000K and so did most of the initially available LEDs lights.

Which Colour temperature is right for my space?

Times have changed, and with it technology which allows for lighting products to be available in all tones within the scale mentioned. This large variety of options available creates confusion and we will need to be more aware of how and when to apply each of these tones of white to ensure we get the most out of our investment. When deciding colour temperature, one must consider the colour scheme/palette used within the space, the intended functional use of the space, and the designer intended emotion or feeling to be conveyed to the occupants of the space.

COLOUR SCHEME/PALETTE
The colour scheme/palette used within the space is essential to deciding the colour temperature of the lighting used as this will have a profound impact on the visual appearance of the colours used within the space. Cooler lights tend to help black, silver, white, blue and green tones stand out whereas warmer lights enhance the appearance of gold, red and wood tones. Similarly, in areas that need equal emphasis of all colours within the spectrum like when displaying merchandise, art or photography, one would advise the use of neutral white lights.

INTENDED FEELING/EMOTION RESPONSE
It may also be of interesting to note that, we have historically developed an emotional response to colour temperature through association. Since the discovery of fire, our ancestors have depended on fire as a source of illumination apart from daylight and we have been hardwired to associate feelings of safety and relaxation from being indoors to warmer colour temperatures as a result. Similarly, daylight/cooler colour temperatures has come to be hardwired to invoke our hunter gatherer instincts from being outdoors. As such, colour temperatures can also be used to invoke emotional responses from the occupants of a space.

FUNCTIONAL USE OF THE SPACE
Similarly, the assigned functional use of the space plays a major role in deciding the colour temperature of the lights to be used. It has been found from research that shorter wavelengths of light has a profound impact on the non-visual photoreceptors within our eyes that lead to the suppression of melatonin, the hormone that regulates our sleep pattern. Suppression of melatonin can be attributed to feeling wakeful and energetic, keeping us sharp whereas higher melatonin levels will have us feeling more relaxed. Warmer colour temperatures have lower levels of short wavelength, blue light whereas cooler colour temperatures that mimic daylight contain higher levels of short wavelength light. Hence, our decision of colour temperatures must depend on the intended functional use of the space as this will determine the wakefulness and energy levels of the occupants. As a general rule of thumb, cooler colour temperatures closer to daylight is recommended within the active workspace where employees carry out their daily tasks and in meeting/conference rooms where mental acuity is paramount. Washrooms, corridors, and pantry areas can maintain neutral colour temperatures whereas breakout areas and reception areas can work with warmer colour temperatures.

Final Verdict

In addition to the above mentioned parameters, it is not recommended to use different colour temperatures within the same space. This will not allow homogeneity of the lights within the space and cause it to look odd.
To summarize, CCT is a means to differentiate white light on the basis of its relative colour. Warmer colour temperatures have a lower CCT and correspond to light composed of higher relative proportions of red colours. As opposed to cooler temperatures which have higher CCT and correspond to higher relative proportions of blue. Warm lights invoke calm and relaxed feelings, and as such are suggested to be used in spaces that require less alertness and need to be more welcoming such as breakout areas, receptions, dining areas, etc. Cool white lights raise occupant alertness and awareness and is recommended for use in spaces that require higher levels of concentration and attention to detail such as workstation areas, meeting/conference rooms, etc. Furthermore, cooler colour temperatures highlight black, silver, white, blue and green tones, whereas warmer lights highlight gold, red and wood tones. As a general and simplified rule of thumb to follow, we would suggest employing warm white lights in a fine dining restaurant or lounge, soft whites in a reception, breakout area, etc. neutral whites in corridors, daylights and cool whites in workstations, meeting rooms, etc. Please keep in mind that very low colour temperatures may leave occupants too relaxed to perform complex tasks with ease and very high colour temperatures may leave occupants feeling over strained or too drained out after sometime.
Recent LED technology allows for lighting systems with adjustable colour temperatures that can be controlled to follow our circadian rhythms and match sunlight patterns to ensure the best working conditions for occupants of the space. These systems can be automated to ensure highest productivity and wellbeing of occupants.
At the end of the day, there can be no steadfast rule that applies to every space. This is where an expert interior design/fitout specialist can come in handy. Our seasoned designers are experts in designing and executing a lighting system that will wow visitors to your space and ensure the health and wellbeing of all its occupants.