The importance of light

By Juliet Rennie

At the end of last year, the UN declared that 2015 would be the International Year of Light and Light Based Technology. By doing so, they recognised the importance of raising awareness of light, as well as its fundamental role in the development of human society.


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Light plays a central role in health, communication, energy, education, agriculture, design and much more. Towards the end of 2014, the Nobel Prize in Physics was awarded to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura for the invention of efficient blue light-emitting diodes (LEDs), back in the early 1990s. Since then, more research has been done into the benefits of LED lighting. For example, LEDs use a fraction of the energy that incandescent bulbs use and they last around 70% longer. In relation to design, the directional nature of LEDs allows the lamps and fittings to be designed for optimum efficacy, enabling the designer to illuminate specific objects or outline a space with light.

Importance of light


The fact that LEDs are also available in a wide range of colours, makes them adaptable for certain spaces, but also puts them at the forefront of research into human centric lighting. Throughout the day our body and behaviour adapts; we release certain hormones which relate to our surroundings, needs and sleep-wake cycles. These patterns are known as circadian rhythms and they have been closely linked to our relationship with light and dark. Fittings containing a variety of coloured LEDs can be easily tuned to a wide range of colours and hues, as well as being dimmed. This capability then gives us the opportunity to have control over the colour temperature and intensity of the surrounding lighting.

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importance of light

With the development of LED technology, lighting manufacturers and designers are increasingly looking towards circadian rhythms and how artificial lighting might be used to compliment and coincide with our sleep-wake cycles. As a result, artificial lighting is now being adapted to imitate daylight and the cycle of the sun. Certain types of light encourage the body to release chemicals, such as melatonin which makes us feel sleepy. Higher amounts of white and blue light, generally experienced during the middle section of the day, contribute to a feeling of alertness, often improving concentration and productivity. Naturally, and in relation to our exposure to light, our bodies should supress the release of melatonin from around 7:30am, making our most productive time roughly mid to late morning. As the day draws into evening and we begin releasing melatonin again, we become sleepier and it is more difficult to focus, until eventually most people fall asleep. Case studies within schools and hospitals have also shown that human centric lighting, when properly controlled, could directly affect our ability to concentrate, reducing the likelihood of error, as well as even decreasing the amount of time it takes to heal after an operation!

However, research has also been done into the possible negative side effects of our 24 hour lifestyles and the fact that we now have access to computers and screens pretty much wherever we are. The widespread use of LED light in our computer, smartphone and television screens means that we are often getting more than our share of short wave blue light, contributing to the suppression of melatonin and thus, our lack of sleep! It is argued that the potential suppression of melatonin caused by artificial lighting at night, could have long term negative effects on our health, including the increased risk of certain types of cancer. Additionally, it has been suggested that the shift to the use of LEDs in exterior could pose a threat to the nocturnal environment worldwide.

Research into the effects of light and ways in which we can use it to our benefit are continuing but,

There is so much more research to be done and the potential to revolutionise the way we see, use and feel light is endless. Directives like the UNESCO International Year of Light only help to broaden our perspective and understanding of the world we live in, now and in the future.

If you’re interested in finding out more about the International Year of Light, or having an explanation of human centric lighting and circadian rhythms from a real expert, take a look at the links below!