The type of light used in a space can be a vital tool in creating a particular atmosphere, writes Luisa Scardovi
Light is a powerful communication tool, and the way it is applied to architecture and objects plays a key role in all projects.
Our perception of luminance is not solely quantitative, it is also qualitative. Light should be functional, but it’s equally important to create the right atmosphere. Do we want to create a comforting and relaxing atmosphere or rather give a feeling of energy? What is the best light for the finishing materials I’m using? These questions can help us identifying a concept, which can then assume the form of a lighting strategy. And when a strategy is in place, it’s time to choose the right tools.
Atmosphere and mood have a lot to do with colour but, in lighting, the familiar expressions ‘warm’ and ‘cold’, refer to a psychological association rather than any physical property of the light. Colour temperature is conventionally stated in the unit of absolute temperature, the Kelvin degree (K). Sometimes it is easy to get confused and to think that the higher the degree, the higher the temperature and therefore the warmer the colour, when in reality it is quite the opposite. Until a few years ago, the light sources available had their own specific colour temperature and were chosen and combined depending on the desired effect or requirements. Today, the same LED fixture can be offered in more than one colour temperature. This gives a lot of flexibility when approaching a project but, paradoxically, it can sometimes be overwhelming.
Applying two different colour temperatures within the same room can help delineate a hierarchy
First of all, we should not forget that the colour of light is always in relation to what it hits. The light’s colour temperature will influence the look of a material in the same way that material will influence the colour of the light that bounces back. An interior based on warm hues or natural wood may look too warm and less bright if flooded with 2,700K, while a grey concrete wall may benefit from 4,000K, although some designers are afraid of using such a cold colour temperature in their projects.
Also, a specific colour temperature could be preferred over another depending on the psychological effect we want to obtain. Let’s say we want to encourage people to come inside a shop or a restaurant. In Oslo we could base our concept on soft and warm tones, while in Dubai we may prefer a colder light for a more refreshing look.
Using the same colour temperature throughout the whole project is not compulsory. Applying two different colour temperatures within the same room can actually help us to delineate a hierarchy or a difference in use, but it can also make surfaces and objects stand out, adding depth to the whole space. This effect is called colour perspective, a trick that painters use to make their paintings more three-dimensional, since warm hues are perceived as closer while cold hues are perceived as more distant.
Ultimately, how many of us have said, at least once: ‘How much I would love that my lamp became warmer when I dimmed it at night, just like the old incandescent bulb’? The latest technology finally gave us LEDs that shift from 2,700K to 1,800K when dimmed, creating a well-known and much-missed feeling of warmth after dusk.
Colour temperature should not be confused with colour rendition.
The colour rendition index (CRI) is the measure of a light source’s ability to show an object’s colour realistically or naturally compared with a familiar reference source – generally daylight. Each light source is tested on eight standard low saturated colours and a value is given to each of them, ranging from 0 to 100, the latter meaning that 100 per cent of the colour is realistically reproduced. Six additional highly saturated colours may be tested to obtain a more precise CRI value. A good CRI implicitly allows us to distinguish colours and to see them more saturated. To understand what a bad CRI means, just think of old street lamp posts equipped with high-pressure sodium lamps. What we could appreciate as a beautiful palette of warm and cold shades during the day, at night became a monochromatic, dull and yellowish background.
If we require a CRI of more than 90, we should remember that this means a loss of 15 per cent in terms of power and intensity in comparison with a CRI of more than 80. Surely the last thing we want to do when shopping is to be forced to step out into the daylight to check that a shirt’s shade is actually red and not fuchsia, but it’s also true that for some projects a CRI exceeding 80 is more than enough.
To conclude, there is not such a thing as ‘the best light’ in absolute terms. The best light is always the one that makes the illuminated object the best version of itself.
Luisa Sacrdovi is a senior lighting designer at Delta Light