The color temperature of light
Light is named by two elements: color temperature and color display. The color temperature of the light (CCT – correlated color temperature) is displayed in degrees Kelvin (K). The temperature of the light used indoors can range from 2000K to about 6500K. The higher the color temperature, the cooler the light.
Therefore, 1200K is referred to as warm light. This is the color temperature of a candle. At 5600K we are talking about cold light. 5600K is equivalent to daylight. Warm light has a red to yellow appearance, cool light has a white to bluish appearance.
Light is also determined by the color display. This value measures how well we can observe colors under a certain type of light. It is used in a color rendering index (or CRI), with a scale from 1 to 100 Ra. 100 Ra represents perfect light, in this case daylight. Therefore, 80 Ra is the norm for most environments; in stores where colors must match daylight, such as paint or clothing stores, the norm is 90 Ra.
Warm light or cold light?
Is it better to use warm light now? Or is it better to choose cold light? That depends on where you need it. At home, warm white light of about 2700K is usually used. They are usually incandescent, halogen or energy-saving lamps. The yellowish glow creates a warm and cozy atmosphere. The color is soothing.
But it’s not ideal if you have to be productive, like at work. Warm lighting in the office is cozy, but creates too large contrasts in the space. Your eyes have to work hard to adapt to this, which is very tiring. Therefore, it is best to place lighting with higher color temperatures (3000 – 4000K) or cool white light (over 5000K) in workstations such as a desk, office or restaurant kitchens.
When looking for lighting for an art gallery, it is best to choose lamps with a color temperature as close to daylight as possible. The lighting will then be very functional and simple and will create a sober and open atmosphere.
the effects of light
It is not only the function of the space that determines the choice between warm and cool light, but also the emotion of the people who live, work or pass through it. Thus, warm light creates a romantic atmosphere, because it recreates the same elements as candlelight. In contrast, cold light, which is closest to daylight, makes people happier and more energetic. To combine both types, it is possible to use dimmable lights. In this way, you can set the mood by dimming the lights at night and give more power during the day.
The design of a lighting plan should always be based on the atmosphere that you want to create in a space. What elements of the space do you want to accentuate and in what way? There are many factors to consider in determining whether it is better to opt for a warm light or a cool light.
Light control
Tunable white
It allows the user to access the full range of white light, from warm tones (around 1650K), to neutral and cool white (around 8000K). Tunable light plays a role in regulating heart rate and regulating the body’s biological clock by improving energy, alertness and overall mood. This natural rhythm produces warmer light in the morning and cooler light in the evening. In a more specific application, it can also help set the desired behavior or mood by specifically cooling or warming a space in counterpoint with the circadian rhythm; its inhabitants may calm down, such as children in a classroom with warm light, or increase alertness, such as in an office with cool light in the evening. The applications that would benefit most would be classrooms, offices, and commercial and residential premises.
Faint to warm
These products, also referred to as warm attenuation, blackbody attenuation or incandescent-like attenuation, mimic the performance of incandescent or halogen attenuation. With an initial color temperature of 3000K at full power, warming towards yellow or red as power is reduced, down to 1800K (the color of candlelight). The applications are endless, but they are most often used in restaurants, hotel lobbies, theaters or residences.
Full color tunable
Also called RGB, RGBA, RGBW, spectrally tunable or color shifting, they can vary their output to create a mixture of light that is white, a tint of white or a fully saturated hue. The unique advantage of this type of color tuning is the ability to move the color spot out of the white light spectrum into a light with a distinctive color for branding or entertainment purposes. It also has the ability to match the intensity and appearance of any other type of light source. It is suitable for applications such as museums, corporate offices, restaurants or theaters.
