What is light?
Light is the visible part of electromagnetic (optical) radiation, its range ranges from 100 nm to 1mm and has been divided into three phases:
- ultraviolet
- visible light
- and infrared.
When the waves reach the desired length, they are picked up by the retina of the human eye. This value is different for each of us, but it is assumed that light is electromagnetic rays with a length of 380-780 nm. In order for us to be able to see anything, the light must reach our eye and cause the so-called visual impression. In addition to creating our reality, light also carries radiant energy, a characteristic warmth that we feel in the rays of the sun or upon contact with a bulb. It is also used by plants in the process of photosynthesis.
Light sources can be divided into:
- natural - stars, including the Sun, lightning, selected organisms (e.g. fireflies)
- artificial - incl. light bulbs, fireplace, candle, LED diodes.
It is also worth mentioning objects that reflect light, but are not its source. These are planets or the moon that emit so much radiation that they appear to be stars themselves. In fact, they only reflect light, creating additional constellations of light in the sky.
The effect of daylight on health
The sun for hundreds of years was the only source of light which, thanks to its properties, became an object of worship in many cultures. Observing nature brought us a fire that started an avalanche of discoveries and amenities that will change our society once and for all. There is no doubt that artificial light has revolutionized human life. It allowed us to extend our functioning also for the time after dark, it allowed to heat rooms and bodies, and it also diversified the menu. Although artificial light has introduced many amenities, it is not able to fully replace daylight. We need it for many metabolic processes in the human body.
Citing numerous studies, it was found that sunlight improves:
- concentration or sleep
- works anti-depressant
- increases our immunity
- and reduces fatigue.
It has a huge impact on our efficiency in everyday activities. It also supports the proper functioning of metabolism, maintaining a healthy weight and appetite.
Lighting emitting natural light
Unfortunately, not all rooms can be illuminated only with daylight. Knowing how it has a huge impact on our well-being and health, when buying lighting for our home or workplace, we should choose neutral color temperature light sources (from 4000K to 4500K). It is also necessary to pay attention to the color rendering index Ra (CRI) - in rooms it should be minimum 80. Then we will be sure that the illuminated items will look natural.
LED lighting allows us to adjust the color temperature or the color rendering index to our needs and the current conditions. It is becoming more and more popular also due to:
- longer durability
- lower electricity consumption
- or maximum light distribution right after switching on.
New lighting systems that, in line with the idea of "Daylight harvesting", adapt to the human biorhythm, also deserve attention. This is done using artificial lighting control techniques that can be dimmed or switched in response to the changing amount of daylight. This change in light intensity is critical to our health because:
- aligns with our biological clock
- regulates hormone levels and body temperature
- and affects our overall well-being.