The effects of lighting on our body
Light affects our body in a range of ways. It is more than just a source of vitamin D. There is research into the effects of light on our sleep/wake cycle, or what is known as our “circadian rhythm”. It reveals that the amount and type of light you’re exposed to may be responsible for how you feel when you wake. Whether you’re a morning person, or a night owl. The quality and type of light also alters our moods.
Natural light has a calming effect on our mood. However a lack of light and even poor quality artificial light can trigger negative moods. Our serotonin levels plummet on dark days, causing negative moods and emotions, whereas sunshine is proven to cause a spike in serotonin and induce a feeling of happiness.
With that in mind, and the fact we spend a large portion of our time under artificial light, lighting design has a major effect on our emotions.
Light Colour Temperature
Daylight, cool white, or warm white? This is always an interesting question. It is definitely not a case of one temperature being superior. Lighting has a complex effect on the human body. Different light levels and colours affect us in different ways. For example;
3000K – Warm White
- This temperature is inviting and invokes a feeling of relaxation. This is great for the home environment and will bring out the richness and warmth of different materials.
4000K – Cool White
- This colour temperature produces a clean, sharper light that complements a modern style, pure white bathrooms and cooler design palettes. Great for “working” spaces, like kitchens or offices.
6000k – Daylight
- While this colour can appear very “white” in closed spaces, it is actually the closest to natural light during the day, and a great source of light to use near outdoor areas where it can help link the two spaces.
The Colour Rendering Index (CRI) is a scale from 1% to 100%, indicating how accurate a given light source is at rendering colour when compared to a reference light source. The higher the CRI the better the colour rendering ability, or the true colour representation. CRI is more important in situations where the differences in colour are important, such as art galleries or museums. Although the CRI should not be overlooked even when designing general lighting for a home or office. Depth of colour is important.
Illuminance vs Lumens
Most light manufactures will publish the output lumens. While this can be a useful indication of the brightness of a light, it does not take into account the light over a given area, taking into account the reflectors/lenses, losses, etc. Therefore illuminance is the best way to compare light levels for your application, as it is the true measure of light on the surface.
Illuminance, or light level, is the amount of light measured on surface. It is measured in lux. 1 lux = 1 lumen/sq meter. As a reference, a sunny day would be around 10,750 lux, an overcast day would be around 1,500 lux.
Designing lighting systems is an in-depth and interesting subject that is often overlooked during the design phase. Utilising shadows and the lack of light is also important when designing.
A few things to consider;
- Colour Temperature
- The location of light sources
- The CRI of the light
- The illuminance, or light level
While lighting design in commercial spaces is focused on, there is little emphasis in the residential sector. If lighting plays such a big part in dictating our emotions, why is so little emphasis placed on the design and quality of lighting in our homes?