What is the color?

We explain what is the color and the different properties it has. In addition, how primary and secondary colors are formed.

1. What is the color?

When we talk about color, we mean an impression produced in our visual organs (eyes), and interpreted by our nerve centers (brain), by a specific light tone of the chromatic spectrum.

All colors are contained in the spectrum of visible light , but in different wavelengths that our perception can capture separately, and identify as specific colors.

The things of the universe are impacted by the electromagnetic radiation of light, thus absorbing part of the light waves and reflecting some others. The latter are perceived by the human eye and identified as the color of things.

It is known that the human eye can capture a finite number of colors  (with many nuances) when it is in a context of much lighting. When light is scarce, on the other hand, we perceive the world in black and white: the superposition of all colors (to reconstitute white light) or the total absence of light, respectively.

White light can decompose in all perceivable colors by means of a prism, as naturally occurs with raindrops in atmospheric suspension, thus giving rise to rainbows.

Within the light visible by the human eye, the light has various energy levels: from 380 to 780 nanometers. So each color has a specific level of wavelength:

• Violet  (380-427 nm)
• Blue  (427-476 nm)
• Cyan  (476-497 nm)
• Green  (497-570 nm)
• Yellow  (570-581 nm)
• Orange  (581-618 nm)
• Red  (618-780 nm)

Below the violet is the ultraviolet light and above the red is the infrared. Neither of us can be perceived by our eyes, although by those of certain animals, and they can also be detected by scientific devices specialized in light. This is of vital importance for astrophysics and also for the theory of color , key knowledge for the art of painting.

2. Color properties

The colors distinguish each other by their wavelength , as we have said. And depending on its purity, one can speak of primary, secondary or tertiary colors. All, however, have the following three properties:

• Matiz . Known as tone or hue, it depends on the wavelengths of the color to place it within the color circle . This is what approximates two next colors in their wavelengths, being able to convert one into the other.
• Saturation . Also known as purity or color, it has to do with the amount of color present at the same time, that is, with how vivid or intense it is, as you move further away from the gray scale.
• Brightness . It depends on the amount of light present in the color, on a scale ranging from black (without light) to white (too much light). A brighter color will present a greater amount of white than an opaque one, closer to black.

3. Primary colors

It is known as primary or primitive colors that are used to obtain the whole set of other colors, that is, the “pure” colors that cannot be obtained by combining the others. This procedure of mixing colors to obtain new ones, is known as synthesis and can occur in three different ways:

• Additive synthesis . The colors overlap, adding light, and thus generating lighter shades. It takes place on computer monitors , TV screens or movie projectors. Its primary colors are red, green and blue.
• Subtractive synthesis . The colors overlap, subtracting light, and thus generating increasingly dark tones. It takes place in prints and photographs. Its primary colors are cyan, magenta and yellow.
• Traditional synthesis . It is used by painting and traditional arts, and although it is also subtractive, it is considered empirical, as it comes from historical experience with painting and mixing oils. Its primary colors are yellow, blue and red.

4. Secondary colours

The secondary colors, of course, are those obtained by the synthesis of the primaries, that is, by mixing them. As we have explained, this will depend on the type of synthesis that takes place, so secondary colors may vary.

• Additive synthesis . The secondary colors are cyan, magenta and yellow.
• Subtractive synthesis . The secondary colors are red, green and blue.
• Traditional synthesis . The secondary colors are green, orange and purple.