Colors of our everyday life (part 1)

The world around us is more or less colorful. At least this is how living beings perceive it (some in this way, others in another way). But what do we actually see and how do we look? To begin with, if we limit ourselves to the physical properties of light - what we perceive with human eyes and call "seeing"visible light", is an electromagnetic wave of about 400 to 700 Nm. This part of the wave is perceived by our eyes as light. Only this one is continuously "divided" into color shades by raising or lowering the frequency.

Thus, we find violet light (approx. 400 Nm) at the lower end of the visible spectrum, while red light (approx. 700 Nm) is found at the other end of the visible spectrum. In between, all the other colors of the "rainbow". Our eyes are genetically deprived of other colors such as infrared (IR) or ultraviolet (UV). Some animals also have receptors in their eyes for this radiation. This helps them e.g. when stalking prey or hiding from predators.


Are we really seeing what we are seeing?

Of course, the feeling of a certain color is primarily a manifestation of our brain, which sends electrical impulses from the retina of the eye to our "processor", i.e. the brain. In the retina of the eye, we have cells sensitive to certain colors, which are called cones and rods - cones are of three types and are responsible for the perception of colors such as red, green and blue (RGB). All intermediate shades are a combination of the intensity of these colors - similarly, the camera sensor works in the same way. Wands, on the other hand, are more intended for light itself (light-dark) and are not sensitive to colors, we use them in low lighting and as a result we do not see such a rich palette of colors. Everything is kind of gray. In twilight, it is so difficult to distinguish the colors of an object and we cannot distinguish well whether it is colored red or green.

Since the perception of light depends on our brain, which adapts wonderfully to different situations, it is of course difficult to build a standard based on subjective perception. Therefore, numerical standards based on physical properties have been developed for reproduction purposes. Such a standard is e.g. built into every digital camera. This, however, is different from our feelings. That is why we are often surprised when we look at beautiful colors in nature, but the captured image is somehow washed out or, on the other hand, oversaturated with colors.

We forget that a sensor is a machine that perceives the wavelength of light ALWAYS THE SAME with mathematical precision. But the brain adapts to the situation and changes this feeling. As an example, we can take a situation where we are surrounded by a slightly reddish light (a classic incandescent light bulb). Under this light, the leaf e.g. paper appears white as it should be, but captured on camera will appear pink. The brain has found a new CENTRAL REFERENCE FOR WHITE and that's how we perceive it - as white. We see, therefore, that we cannot be excessive in our eyes.