If you asked most people, they would probably say that “sight” was the most important of their six senses. No one wants to lose their ability to see. But what can we actually see, in reality?
In contrast to technical optics, so-called physiological optics deals with the theory of visual perception (sight, colour perception, and optical illusions).
In principle, “all we can see” with our eyes is light. To be able to turn that light into a detailed image, our eyes have to be able to quickly evaluate a large number of different light waves and transmit that information to the brain. These light waves determine the properties of the light: Direction, brightness, and colour.
But where does colour come from? Colour phenomena can also be categorised. We see colours,
when light is transmitted within certain ranges of wavelengths, for instance by fireworks.
when our retina is irritated (for instance by rubbing your eyes).
when light is split and reflected in different directions, such as in a rainbow.
when light enters the eye through reflection from the surface of a body and its composition differs from that of the light source. In this phenomena, part of the light is absorbed, and part of the light reaches the eye.