Introducing Tunable White

Published 26 May 2015


Tunable White Technology Design Methodology – Natural Lights for Humans

Our biological clock

Since the dawn of time, light has guided us, our biological clocks have been controlled by the sun and the quality of light changes over the course of the day. The biological clock is also called the circadian rhythm (from the Latin circa dies, “about a day”); natural light and its array of colours define our circadian rhythm, our waking and sleeping hours.


Eventually we created artificial lighting and we became independent of daylight. We were able to work into and throughout the hours of darkness. Our biological clock can become disturbed doing this.

Science behind managing our biological clock


We feel best when exposed to natural light outdoors, where the intensity and colour changes over the day. The morning light comes in at low angles, telling us to wake up and prepare us for the day. As the sun rises higher, light enters the eye from higher angles. It enters the bottom of the eye, stimulating our ganglion cells, producing the hormone cortisol which wakes up it. These ipRGC’s (intrinsically protosensitive retinal ganglion cells) are often referred to the third receptor.


The light that hits the bottom of the eye in combination with colour temperature of the sky and the shadows tells our brain that it’s time for activity; we need to collect food to survive until the next day. Later, when the sun starts to go down and the light coming from low angles, the production of the sleep hormone melatonin starts and this prepares us for a night’s rest.

Effects of light intensity and colour temperature

Our preference for colour temperature isn’t static; sometimes we want a cold, activating light, others times a warm relaxing temperature is preferred. Our preferences for light can also differ with age; the young are inclined toward a colder light while as we get older, this changes to warm.

We are increasing become accustomed to being able to adjust and select our preferred settings in our working lives. While it is often possible to set or change the intensity of the light, the colour temperature is dictated by someone else. In a hospital waiting room or a dentist surgery, for instance, a colder light level may not create the peaceful ambience we crave.

Tunable White Application in Waiting Room.

In an open plan office it is hard to get a very personal lit experience but changing the colour temperature control can still enhance the ambience of the space. Other areas such as lobbies, receptions, conference room, cellular offices and waiting rooms are ideal environments for a tuneable white solution.

Activating light showers

The colour temperature and intensity of light can change depending on the season too. Often, in an office environment, our artificial lighting installation doesn’t reflect the actual lighting conditions outdoors as it would be very dark in the room during some of the the darker winter months. However, during the dark months we can stimulate the circadian rhythm with lighting at particular times during the day. This may result in the use of a lower levels of warm light first thing in the morning and choosing to increase intensity and use cooler light to stimulate an emotional response in the office of “let’s get productive”.


“Light showers” in high levels of cooler light for short periods or other activating a warmer setting to evoke a more relaxed mood to suit a particular task. To activate and promote concentration, we can “shower” in high levels of cold light for short periods throughout the day. Studies in school environments have shown positive changes in activity. This could be applied as activating light boost after lunch when the body’s systems are fully occupied to digest food.

Design methodology of the Tunable White Technology

Tuneable White technology permits the user to alter the colour temperature and intensity to what they prefer within the same luminaire. By designing good lighting systems, lighting can help increase concentration and motivation and to improve subjective and objective well-being. Personal control allows us to get productivity boosts when required, to regulate the light depending of task, mood or situation. As well as readying ourselves to slow down toward the end of the day and help us prepare for sleep.

Cool light

Warm light

The design methodology of Tunable white technology is simply to imitate natural light in both level and colour during the day. Dynamic lighting is like music for our eyes and mind, increases comfort and well-being by mimicking natural light for better sleep and reducing stress. We call it Daylight mimicking. The fact that blue light activates and warm light calms is all about imitating the natural light and its variation that has controlled our biological clock since the origin of life.



Part 2
The technique is simple

The LED modules contain a mixture of diodes providing warm or cool light. By mixing the light from these diodes we can get colour temperatures between 2700–6500 Kelvin out of a single luminaire. Everything is controlled via DALI Device Type 8 and can be managed with different types of control units. For an automatic dynamic control of colour and intensity a router system that dictates the levels over time is used.

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DALI Device Type 8

DALI ballasts that are compatible with DALI Device Type 8 provide functionality for controlling colour temperature.

DALI ballasts that are compatible with DALI Device Type 8 are controlled with only one DALI address that controls both the cold and the hot diodes.

The function with different colour temperatures requires no programming with respect to the mixture of cold and warm light since the logic is built into the devices. The desired colour temperatures for different scenes are set directly in programming.

Conversely, when using DALI ballasts which does not communicate according to DALI extension 209 (as opposed to the Type 8 described above), two ballasts are required: one for the warm and one for the cold diodes. To achieve the varying colour temperatures, each level (i.e. 3000k, 4000k, 5000k) has to be both measured with a spectrometer and individually programmed.

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Technically, it’s not that complicated. Everything is controlled with a DALI Device Type 8 and can be implemented with different types of control units depending on what you want to achieve. If you want to imitate daylight in colour and intensity automatically, use a router system, otherwise it is often enough with a generic control panel, simple button panels or touch panels to control manually.



Part 3
Tunable white in applications - 
Create your personal light!

Here are a few examples of where the tunable white technology can be used.

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Better light in the conference room

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Conference rooms are often located in the middle of the building without access to daylight. It is an area where the colour temperature control can be used in several ways. A cooler light applies when more active tasks are being performed or a warmer light when we need to focus. A common issue when using video conferences is that the camera is unable to handle the light levels as well as the human eye, so we are perceived as looking more sickly. With a Tuneable White solution, we can adapt the light level so that the faces of the participants are rendered as realistically as possible, helping to facilitate the communication process. In this application, Pleiad Wallwashers are used to vary the light on the walls to get exactly the right light for every task.

All light on me – the auditorium

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Education or full-day conference? As well as having scenes with different lighting levels, it is advisable to also control the colour temperature. By using a timer control the colour of the light provides the participants with an idea of the time of day. Alternatively, we can use the colour temperature to create different scenes. Refreshing high levels of cold light for activity or warmer dimmed light for focus and concentration. The light on the presenting area is controlled separately depending on what activities are going on there.

Activity or rest in the breakout room

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In breakout rooms the benefits of colour temperature control are in their element, transforming how you can use the space. Use of cool light revitalises us while a warmer light calms us down. In this example we have chosen recessed Pozzo. The large, wide beam distribution creates a light-well effect, giving an impression of natural light, further optimised with a varying colour temperature which imitates the evolution of daylight throughout the day.

Welcoming in – the entrance or waiting room

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In the entrance or the waiting room light is controlled with a router solution to imitate daylight, both in intensity and colour. This can be especially important if there is no natural daylight reaching in the room. This solution provides a sense of having access to daylight, even if the room is located in the middle of the building where there is limited access to the real thing. Pozzo creates a feeling of natural light wells, reinforced by adding light on the walls with Pleiad Wallwasher G3.

Personal light in the cellular office

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A cellular office is the easiest room to apply a Tuneable White solution as there is only one user who controls the light according to his or her preferences. Think of a cold, intense light when you want to activate yourself or a warm dimmed light for conversations, reading and tasks which require concentration. Using a suspended direct/indirect Combilume, supplemented with Pleiad Wallwasher G3 , provides the ambient and task light requirements, with the colour temperature and intensity controlled via a simple panel on the wall.

Dynamic in the open plan office

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Open plan offices cannot be controlled to reflect each individual’s personal preferences since the room is lit for a group of people. Here we recommend a router solution that varies the light over time and adjusts the colour temperature mimicking the light outdoors. In the ceiling we have Multilume Flat  and, to strengthen the sense of a natural daylight, the walls are lit using Pleiad Wallwasher G3.





Part 4
Tunable white products

combilume products



Marathon is a stylish spotlight designed for track systems. Available in three different sizes its cylindrical shape and clean design makes Marathon a spotlight ideal for any setting. Produced in a dramatic black or subtle white finish, the luminaire housing and ballast are constructed of aluminium and the front ring of thermoplastic. Positioning the direction of Marathon is made easy, the luminaire can be turned through 360° and the luminaire housing can be angled 0–90°.




In Combilume, LED technology is really in its element.

The modern light technology and side-emitting light diodes result in pleasant, even surfaces both for individual office work stations and for large rooms where people come together.

Equipped with Tunable White, Combilume becomes the creative lighting for the whole project with the possibility to set the colour temperatures from 2700 K to 6500 K.

combilume product whole

Pozzo Delta

pozzo delta

Pozzo is like a little piece of the sky, a light well in the room where it is not possible to get the real thing. Inspired by natural light, Pozzo gives a pleasant natural light feeling. Pozzo with Tuneable White provides another opportunity to mimic daylight where the colour temperature can be regulated as the day passes.

Multilume Flat Delta


Multilume Flat has a completely level smooth surface which follows the surface of the ceiling, resulting in a stylish and discrete appearance.

Multilume Flat’s balanced work and general lighting delivers excellent light comfort, constantly updated with the latest LED technology.

Lighting control and Tuneable White makes a sustainable and flexible office lighting.

Multilume Flat Delta

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Pleiad Comfort G3


Thanks to an innovative Anti-Glare Control ring, Pleiad G3 harnesses the efficiency of the LED lightsource without compromising on the ergonomics. Further enhanced with Tuneable White, they create bright and flexible environments where people thrive to reside and work.

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Pleiad Wallwasher G3

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A wall washer has its place in offices, lobbies and other public spaces.

Pleiad Wallwasher G3 harmonises with the other luminaires in the room, and, when equipped with Tuneable White, it also provides an opportunity to create a more dynamic lighting with different colour temperatures.

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