How important is daylight?

How important is light?

One of the main defects arising from our modern civilization is to spend most of the day indoors. This eliminates the beneficial daylight from our lives, but our bodies need full spectrum daylight during the day

As early as 1796, the German physician Christoph Hufeland published in his "Makrobiotik" that man becomes limp, pale and apathetic as a result of the lack of daylight and that people who are locked up in a dark dungeon for a long time eventually lose their life energy.

The discoverer of vitamin C, Nobel Prize winner Albert Szent-Gyorgyi, recognized how strongly we are influenced by daylight and colours. He said that all the energy we take into our bodies is ultimately derived from the sun. He discovered that enzymes and hormones that play a role in the process of energy transfer have their own colour and are very sensitive to light. These light-induced processes have a major impact on the body. (A. Szent-Gyoryi , Introduction to a Submolecular Biology-60 and Bioelectronics-68, Academic Press, New York)

The researchers Martinek and Berzin also established that light and colour influence the enzyme systems and biological activities in our body. They suggested that some colours of light could stimulate specific body enzymes. ( Martinek-Berzin, Artificial Light Sensitive Enzymatic Systems as Chemical Amplifiers of Weak Light Signals, Photochemistry and Photobiology 29, Mar '79, pp 637-650).

All studies show that the human body is particularly sensitive to light and because we perceive light with the eyes, the eyes not only have the function of "seeing", but also "receive". (Liberman, Light medicine of the future, ISBN 9020242989-p. 34 ff).

The pineal gland also plays a major role in the light reception and light processing of the body. It is the light meter of the body. The pineal is no bigger than a pea, but it receives light-activated information from the eyes through the hypothalamus; on the basis of this, the organ controls hormones that have a major influence on body and mind. The activities are regulated by light changes in the environment. In birds, salamanders and fish, light stimulates the pineal gland by directly penetrating the skull. In many reptiles, the pineal gland has all the light-sensitive receptors that are characteristic of the eye, which is why it is also called the 'third eye'. In all hairy animals and humans, light stimulates the pineal gland exclusively through the eyes. (Reiter, The Pineal Gland: an important link to the environment NIPS, vol 1, 86, pp 202-205).

The pineal gland also controls the hormone melatonin. The excretion of melatonin should follow a regular, daily rhythm. The hormone is secreted in response to nightfall. The melatonin level reaches the highest level at night (between 2 and 3 a.m.) and then falls and around noon (12 noon) the lowest level is reached, before rising again. (Benningfield, Spring Forward, Spirit, '90). This ability of the pineal gland to sense whether it is light or dark outside, to tell the body whether to be active or to rest, allows our biological rhythms to run smoothly. We are literally “beings of light”. (Liberman, Light Medicine of the Future).

Looking, seeing, should be effortless. Without a trace of effort. Once the lighting conditions are not right, our eyes have to constantly work overtime because our eyes absorb most of the light. Light and colour are inextricably linked. Only full spectrum light really reproduces the colours, the eyes can now perceive colours without effort and see well. As soon as there is poor artificial light in the room, the eyes have to put in a lot of effort and the natural image is still not seen.

The visible part of the light spectrum perceived by our eyes are the colours of the rainbow. Violet, indigo, blue, green, yellow, orange and red, with violet having the shortest and red the longest wavelength. These colours are an important key to the evolution and functioning of humans. In humans, light has a major influence on physiological and psychological functions: fertility and mood.

This can be seen very clearly in countries such as Norway and Finland where it remains dark in the winter months. In these countries, a direct link has been shown between reduced daylight exposure and increased irritability, exhaustion, insomnia and depression. On the other hand, it has been shown that during the months of June and July, when the sun shines for about twenty hours, more children are fathered than in the winter months. (E. Keister Jr. “Living without Light.” Science Illustrated 2, no. 7, March '89, pp. 26-32).

Fortunately, the idea that light is an integral part of all life forms is gaining ground in this century. Nowadays, more and more attention is paid to natural light in new buildings. Where this is not possible, artificial light sources are used. Colour rendering is important with artificial lighting, a CRI above 95 is important to create a natural and healthy indoor space. Since its inception in 1960, True-Light has been engaged in the production of full spectrum daylight lamps and daylight LED lamps that already reach a CRI 98. In this way they contribute to a healthy living environment indoors

The colour industry and metamerism.

To properly measure the composition of light, the eye should be able to see all light frequencies well. In reality, for distinguishing colours, the eye has three different types of light-sensitive cells in the eye, cones. To get an impression of white light, the three types of cones in the eye must be stimulated equally. This can be done with real white light (with a flat spectrum) or with the combination of coloured light, as long as the cones are stimulated equally. The colour impression of an object is determined by the radiation of the light source and the reflection of this light on the object. All these different compositions are called metamer.

Metamerism is the basis of the paint, photo, fabric and -all working with a computer screen- industry. By mixing a small number of colours, for example red, green and blue, a large part of the colours can be approximated. However, those approaches turn out differently under different circumstances, which we call a metamerism error.

Metamerism is the appearance that two objects appear to be the same colour under certain conditions, while a colour difference can be seen under other conditions. The spectra of two different light sources are metameric if the colour of those sources is the same to the human eye. In daylight one sees large differences in the colours, while under "warm (yellow)" light those colours all appear the same colour. That is why full spectrum daylight is so important in determining colour.