The sixth chapter of Studio Due review is dedicated to Lighting Designer Herward Dunkel and his human-centered approach to Lighting Design.

Herward’s article discusses the connection between light pollution and human health underlining how the “wrong light” can impact us and the planet.

Light is life and good light is vital for all living beings.

Light has always been an elementary part of human life, maintaining our physiological functions, controlling neural and hormonal processes, providing vital day-night rhythm and influencing our performance and mental state.

For the hominids, light was already a guarantee of protection and orientation by night. The discovery of fire as the most natural artificial light source is considered one of the most significant steps in human evolutionary history. In all independent cultures, light is one of the most weighted phenomena and is consistently associated with positivity.
In the teachings of Plato, light assumes the metaphor of the state of complete knowledge.
Nowadays,  in times of LED technology and lighting design, the availability of artificial light is a completely self-evident state, nevertheless it has a fundamental position in our everyday lives.
Not only does it allow us to literally turn night into day, it has become irreplaceable in our daily lives, culture, medicine and science.

Just think of the screen on which you are most likely to read this humble post.
Yes, this is a lightsource too.
Researchers, especially in recent years, have increasingly been revealing the downsides of the excessive use of artificial light and demonstrating their only the initial effects on humans and  the environment. And, in terms of environmental policy, the demands for facility management and energy efficiency are ever increasing.

What is light?
Light is the part of electromagnetic radiation that is visible to the human eye. The visible part of the electromagnetic waves forms the light waves, which cover a range from violet with 380nm to red with 750nm. Nevertheless, the entire range of light waves cannot be experienced by the human eye. For example, the maximum visibility value per day is 555nm, which is in the yellow-green colour range. At night, this visibility value moves to the short-wave red-violet colour range, which is at a maximum value of 507nm.

In the morning, light has a high blue content resulting in less melatonin being produced and enabling cortisol to function better during the time of getting up. In the evening it is exactly the other way around: weak and yellowish light promotes the release of melatonin and makes you relaxed and tired.  
In the following, the essential aspects of light and artificial lighting will be shown and addressed. The focus is above all on our humankind’s elementary desire for light and the associated position of artificial lighting in our everyday lives.
Especially in winter, little daylight  and cloudy skies quickly make you tired.

The hormone balance explained below works the same every day.
You may have experienced yourselves, shift work or long-haul flights to another time zone cause sleep problems which are influenced by light and the body’s internal clock being forced or brought out of it’s natural cycle.

In summer, when the sun rises earlier, it is also easier for most to get up, as the early incidence of light makes cortisol production begin earlier. This mechanism works very well with natural light, however artificial light can confuse this cycle.
Blue-tinged light in the evening, like that of smartphone and TV screens, disturbs the production of melatonin.
In the morning you are often sleepy and not very relaxed. However, this physiological mechanism can also be advantageous: early in the morning, blue-tinged light helps us to wake up. All of the aforementioned changes affect people's hormonal balance.

In winter, especially in the increasing geographical latitudes, it is important to make use of the little daylight there is. In the winter months, 20 to 30 minutes under cloudy skies is usually sufficient to get enough light and UV radiation.The use of artificial light with solar spectrums, such as solariums or a daylight lamps can support this.
Exposing yourself to sunlight for a short time is not a problem for the skin and also has a great health advantage: the production of vitamin D starts with the sun's rays. Vitamin D is difficult to absorb through food and a deficiency of vitamins usually manifests itself in a poor immune system.

Scientific studies confirm the link between daylight deficiency and various physical and mental problems.

Most of us spend 90% of our time indoors, two-thirds of which are at home, and more than 40% of the world's population suffers to an extent from seasonal depression.

This leads to the conclusion that, especially in closed work rooms, day/sunlight should be reproduced as well as possible, above all in order to motivate employees with the additional benefit of reducing absenteeism as well as the effects mentioned above.

Artificial light, especially the wrong kind of light, however bright, is not a substitute for the benefits of sunlight, which acts as a natural antidepressant.


Since the electrification of cities, artificial light sources have become an elementary part of life and have become indispensable, especially in urban areas.
Here they often pick up the difference between day and night and make sure that life is still safe even when it gets late and sunlight diminishes.  

However, the constant availability of light has downsides, precisely because, in a completely shifted or derailed day-night rhythm for humans , artificial light sources also be observed as having considerable consequences for flora and fauna.

The totality of the different light sources, in many places leads to an unnatural brightening of the night sky, and has serious effects on the animal world in particular.

This is also reflected in a pre-arrangement of the breeding seasons of birds. Migratory birds orient themselves by the moon and stars, unknown large light sources cause temporary disorientation.
Insects and other animals around the globe are also affected by the effects of artificial light. Night-active species are attracted by street lights or well-lit advertising areas and, depending on the light density and the respective light distribution, this leads to a massive disturbance of the breeding deposit of sea turtles, which leads to a depletion of the species in the long run.

Lighting systems that produce so-called light losses, i.e. unnecessarily radiate horizontal or upward lights, are one of the main causes of excessive light emissions in urban areas.
UNESCO is therefore endeavouring, as part of its programme, to enforce the shielding of light sources, thereby preventing unused radiation which of course, also has the positive effect that the illuminated objects need to be illuminated more concisely and with less force. Naturally, this also has the positive effect that the illuminated objects can be lit more concisely and with less force/strength/brightness/energy.

But it is not only the environment that suffers in the long term from the artificial brightening of our world. Excessive light emissions can also become a disruptive factor for humans that should not be underestimated. At home especially, Foreign light, for example from neighbourhood street lights, can become an unpleasant nuisance.
There are also more and more efforts to reduce the stray light so that you can still admire our wonderful starry sky in extra-urban areas.

Light is important, day in,  day out and the positive effects of the light that we have been able to enjoy until now and which have contributed so much to our well-being should continue to be enjoyed in the future. Above all, with respect for us and our planet.