Of all the information that we take in from our surroundings, 80% comes through our eyes. The data transfer rate is ten times greater than for hearing. Three-dimensional or stereoscopic vision is possible because we have two eyes a certain distance apart. When we focus on an object, both our eyeballs are directed at it. The patters that this object creates on our retinas differs slightly in each eye because of the different perspective, and our brain uses all this information to "compute" an impression of space so that we can judge distances.

When we look across a landscape our brains distinguish between objects close by and those further away by the blue component in the light from these objects. Objects near by appear in warmer and more intense tones whereas objects far away appear in bluish and pale tones.

In order to see, human beings make use of electromagnetic radiation in only a small wavelength band between 380 nm and 780 nm. This band is called visible light.
In the course of evolution our eyes have adapted specifically to the wavelength band of the solar spectrum, which manages to penetrate the earth's atmosphere in sufficient quantity and with a certain constancy.

We are able to see in color because we have cone receptors in out eyes that divide light into three different spectral ranges. One type of cone is sensitive to each of the three radiation ranges that we call red, green and blue. As these different types of cone are triggered the brain can cover the entire color spectrum by the process of additive color mixing.

The human perception system uses the following information:

Human perception is greatly influenced by the choice of light source with its specific properties in terms of light colors and color rendering.

L = r * E
 
L: Luminance
r: Reflection coefficient
E: Illuminance