Today, we use lighting not only to dispel the darkness. The aspects of design and atmosphere have become increasingly important. Lighting design must therefore not only be functional, but should also be functionally beautiful. An original design for a lamp is impressive, but that is not all. The light (or more precisely: the colour temperature of the light) has a great influence on the interior design and the atmosphere in the room. It not only determines how a room looks, but also affects how people feel when they are in that room. This feeling is strongly determined by the placement of warm or cool light.
Light is determined by two factors: colour temperature and colour representation. The colour temperature of light (CCT – correlated colour temperature) is expressed in degrees Kelvin (K). The temperature of light used indoors can range from 2000 K to about 6500 K. The higher the colour temperature, the colder the light.
At 1200K we therefore speak of warm light. This is the colour temperature of a candle. At 5600K we speak of cold light. 5600K corresponds to daylight. Warm light appears red to yellowish, cold light appears white to bluish.
Light is also determined by the colour representation. This value measures how well we can perceive colours under a certain type of light. This is expressed in a colour rendering index (or CRI) with a scale from 1 to 100 Ra. 100 Ra stands for perfect light, in this case daylight. 80 Ra is therefore the standard for most environments; in shops where the colours should match daylight, such as paint or clothing shops, the standard is 90 Ra.
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 with about 2700 K is usually used. These are usually incandescent, halogen or energy-saving lamps. The yellowish glow creates a warm, cosy atmosphere. The colour is calming.
But it’s not ideal when you need to be productive, like at work. Warm light in the office is cosy, but creates too much contrast in the room. The eyes have to get used to it, which is very tiring. It is therefore better to use lighting with higher colour temperatures (3000 – 4000 K) or cool white light (above 5000 K) at workplaces such as desks, offices or restaurant kitchens.
When looking for lighting for an art gallery, it is best to choose lamps with a colour temperature that is closest to daylight. The lighting will then be very functional and simple, creating a sober and open atmosphere.
It is not only the function of the room that determines the choice between warm and cool light, but also the emotions of the people who live, work or pass through it. Warm light, for example, creates a romantic atmosphere because it replicates the same elements as candlelight. On the other hand, cold light, which is closest to daylight, makes people more cheerful and energetic. To combine both types of light, you can use lamps with a dimmer. This way, you can determine the atmosphere by dimming the light in the evening and giving more light during the day.
Planning a lighting plan should always be done depending on the atmosphere you want to create in a room. Which elements of the room do you want to emphasise and in what way? There are so many factors to consider when deciding whether to go for warm or cold light.