Where Colors Come From

The world around us is colored and bright colors are found everywhere. The grass is green and the sky is blue. An orange is orange and a cat is gray. All of these are colors. But where do they come from?

Vision is organized in such a way that we see light rays that have interacted with an object and then hit our retina. These rays can be refracted or reflected. Most often we see reflected rays and it is these rays that paint the image of the object in our eye.

Pure light has a white color. But what is color? Once again, let's remember that light has a wave nature. It is an electromagnetic wave. Every wave, mechanical or electromagnetic, has a length.

White light does not have a specific wavelength, and therefore has no color. It is a group of streams with different wavelengths, which together affect our eye, forming white color. There is no white light in nature. It is the result of exposure of the eye to light radiations with different wavelengths.

There are seven basic colors. They are electromagnetic waves of different wavelengths. They are also called monochromatic radiations. Shades such as pink, lettuce or lilac are formed by mixing several monochromatic radiations with different wavelengths and have no monochromatic radiation of their own.

White light can be decomposed into colored components. These colored components are called a spectrum. Spectra are bands of color that alternate one after the other. This was first observed by I. Newton. He was repairing a telescope and noticed that at the edges of the lens on the beam of light that passed through it formed a rainbow. Here we encounter a new concept called dispersion.

Now for the most interesting part. Why, for example, is a green apple green in color? Color is the ability of objects to reflect or emit light waves of a particular part of the spectrum. We remember that light that falls on an object is reflected off of it and sent to our eye.

But light is reflected from different bodies in different ways. Some of the waves with a certain wavelength from the spectrum are reflected from the object, and some are absorbed.

In the case of the green apple, white light fell on the object, which, as we remember, consists of seven basic monochromatic radiations, and the object absorbed all the radiations except green. The color with the wavelength characteristic of green was reflected and came into our eye. We saw it, but the other wavelengths were absorbed.

Black is the color of total absorption. There is no reflected color as such. White, on the other hand. Total reflection of all seven colors of the spectrum. I think this explains why a white car heats up less in the sun, while a black car almost melts.

As such, the color of an object at the physical level is determined by many factors. Predominantly, the structure of the sample plays a role. For example, if we consider white snow, we are dealing with a huge number of surfaces for reflection. After all, its porosity is enormous. As a result, we see scattered light rather than reflected light. And we perceive it as a white color.

What happens if sunlight falls on a blue-painted wall? Only the blue rays will be reflected from it, and the rest will be absorbed. That is why we perceive the color of the wall as blue, because the absorbed rays simply do not have a chance to get to the retina.

Different objects, depending on what substance they are made of (or what paint they are painted with), absorb light differently. When we say: "The ball is red", we mean that the light reflected from its surface affects only those receptors of the retina that are sensitive to the color red. This means that the paint on the surface of the ball absorbs all light rays except red.

An object has no color in itself; color is produced by the reflection of electromagnetic waves in the visible range. If you are asked to guess what color a piece of paper is in a sealed black envelope, you are not at all wrong if you answer: "Nothing!". And if a red surface is illuminated with green light, it will appear black, because green light does not contain rays corresponding to the red color.

So it turns out that no object is colored by itself. Color arises from the selective absorption of visible light by a substance. And since there is a great number of substances capable of absorption - both natural and man-made - in our world, the world under the Sun is colored with bright colors.