Introduction to color theory

We begin to explain color theory, a fundamental part of any graphic design and web aesthetics in particular. Nature of color and its perception.

We are surrounded by colors. These are part of life itself, and the human being is one of the privileged beings of Nature to be able to enjoy them.

When we go down the street, when we are working or enjoying our free time or when we are browsing the Internet, we constantly receive color impressions through our eyes, and these impressions have the power to excite us, calm us down, put us in a good mood or to inspire us with pity. It is the world of color.

And if this aspect of life is important in each and every one of its facets, it is even more so in the world of design. It is perhaps one of its fundamental parts, and even more so in web design, since we have very little space and very little time to be able to express the soul of our site and adequately capture the attention of our visitors, and color is the first form of communication between a web page and the user.

It has been shown that the first nine seconds in which a person views our page are crucial, and it depends on them whether they continue browsing our site with pleasure, do so indifferently or leave us. And from what you see in these seconds what perhaps most calls and captures your attention is the distribution and the range of colors of our page.

This importance of color extends to all the arts, although a painter, for example, has much more time than we do to express himself with colour. It also has an almost infinite range of colors, while we web designers have only a few colors to express what we want (and we’ll see later how few colors we really have at our disposal).

In this chapter we are going to see a bit about the world of color in general, its application to graphic design and the restrictions that we are going to have when working with colors in the design of a website.

nature of color

We can see the things around us because the Earth receives light from the Sun. Our mother star constantly floods us with its light, and thanks to it, life on our planet is also possible.

Sunlight is actually made up of a wide spectrum of electromagnetic radiation of different wavelengths, forming a continuous spectrum of radiation, ranging from very small wavelengths of less than 1 picometer (cosmic rays), to wavelengths of very large waves, of more than 1 kilometer.

The human being is only capable of visualizing a subset of them, those ranging from 380 (violet) to 780 nanometers (red), as we can clearly see if we pass it through a prism, an effect discovered by Newton.

Each wavelength defines a different color (emission colors). The sum of all colors (wavelengths) results in white light, with black or darkness being the absence of colors.

If, once the sunlight has been decomposed into its constituent wavelengths, we rejoin them with another prism, we will once again obtain white light.

color perception

Well, we already know where the colors come from, but how can the human eye see these waves and distinguish them from each other? The answer to this question is found in the human eye, basically a 2 cm diameter sphere that collects light and focuses it on its posterior surface.

At the back of the eye there are millions of cells specialized in detecting the wavelengths coming from our environment. These wonderful cells, mainly the cones and rods, collect the different parts of the spectrum of sunlight and transform them into electrical impulses, which are then sent to the brain through the optic nerves, which is responsible for creating the sensation of color. .

The cones are concentrated in a region near the center of the retina called the fovea. Its distribution follows an angle of about 2° from the fovea. The number of cones is 6 million and some of them have a nerve ending that goes to the brain.

The cones are responsible for color vision and it is believed that there are three types of cones, sensitive to the colors red, green and blue, respectively. Given their way of connecting to the nerve endings that go to the brain, they are responsible for spatial definition. They are also insensitive to light intensity and provide photopic vision (vision at high levels).

The rods are concentrated in areas far from the fovea and are responsible for scotopic vision (low-level vision). The rods share the nerve endings that go to the brain, and therefore their contribution to spatial definition is not very important. The number of rods is around 100 million and they are not sensitive to color. The rods are much more sensitive than the cones to light intensity, which is why they contribute aspects such as brightness and hue to color vision, and are responsible for night vision.

There are groups of cones specialized in detecting and processing a certain color, the total number of which are dedicated to one color and another being different. For example, there are more cells specialized in working with the wavelengths corresponding to red than any other color, so when the environment we find ourselves in sends us too much red, information saturation of this color occurs in the brain, causing a feeling of irritation in people.

When the system of cones and rods of a person is not correct, a series of irregularities in the appreciation of color can be produced, just as when the parts of the brain in charge of processing this data are damaged. This is the explanation of phenomena such as color blindness. A colorblind person does not appreciate the ranges of colors in their proper measure, confusing reds with greens.

Because the color identification process depends on the brain and the ocular system of each specific person, we can accurately measure the wavelength of a certain color, but the concept of the color produced by it is totally subjective, depending on the person itself. Two different people can interpret a given color differently, and there can be as many interpretations of a color as there are people.

In reality, the mechanism for mixing and producing colors produced by the reflection of light on a body is different from that of obtaining colors by direct mixing of light rays, as occurs with a computer monitor, but in broad strokes and at a practical level the concepts studied up to now are sufficient.