Introduction

Colors are different wavelengths present in white light. When one of the wavelengths is dominant, we observe light with color, because our eyes cannot distinguish the colors when they have large differences of intensity. If the intensity of a light beam is very high for red and very small for the other colors, we see only red.  White light is formed from a combination, with equal intensity, of all waves of the visible spectrum.

The primary colors are those from which all colors are formed. This is because their intensities are higher in different parts of the visible spectrum, so by taking a combination of them and varying their power, new colors appear. The primary colors are red, green and blue.

When mixed, the phenomenon is described as addition of colors. If instead of taking red, blue and green, we join cyan, magenta and yellow (resulting from the mixture of the three above) the result is the primary colors plus black. This is called subtraction of colors.