Instead of putting the emphasis on illuminating task areas, there is now increasing focus on obtaining illuminance which improves the comfort and therefore the productivity of the end-user. There has always been an ergonomic element to artificial lighting but with the advances in LED lighting technologies enhanced user confort is being pushed to the force of modern lighting systems.
It has long been recognised that lighting affects mood, and since the recognition of Seasonal Affective Disorder (SAD), it has become more well-known. During winter months and times of reduced natural daylight, sufferers can experience severe depression, the symptoms of which can be reduced with the help of naturally coloured artificial lighting.
Adaptive colour-changing lighting is not a new concept, but the LED revolution has meant that is now a much more feasible approach to lighting. Studies have shown that there are benefits both to comfort and to productivity. The human body has natural rhythms which are directly influenced by levels and colour of natural daylight. These making us more alert, while warmer tomes of lower intensity, blue-hued light during mid-morning stimulates serotonin production making us more alert, while warmer tones of lower intensity light towards the end of the day signal the beginnings of melatonin production readying us for rest and sleep.
A recent discovery of another type of structure within the human eye has furthered interest in circadian rhythms and how we can engage them. We have long known of rods (peak sensitivity 498nm, green-blue light) and cones (peak sensitivity 555nm, green-yellow light) but newly-found structures, the intrinsically photosensitive retinal ganglion cells (ipRGCs) have shown to be linked to mental awareness and are sensitive to wavelength approx. 470nm (blue part of the visible spectrum).
These relationships between light and human responses have now become part of a construction industry standard, the well standard which comprises seven areas for assessment: