Throughout history, the perception that color was the result of combining light and darkness remained among theorists and scientists until the 17th century. After constant practices and experiments of projecting sunlight onto a body through a prism by various physicists and researchers, which generated colors, the first approximations on the functioning of light are attributed to Isaac Newton, who proposed the first color theories still valid to date in our modern society.
The popular experiment of projecting light onto a prism giving rise to the rainbow, which has been carried out both intentionally and by chance, was the experiment that gave Newton the key to proposing his own theory that would contribute to understanding the phenomenon of colours.
In 1665, the physicist, theologian and inventor Isaac Newton (1642-1726) launched the well-known and renowned practical experiment of double light refraction: inside a dark room, a ray of natural light is projected onto another white body. This ray of light is intercepted by a prism, resulting in the seven colours that make up the rainbow: yellow, red, orange, violet, green, blue and cyan. The 17th century experiment was the first demonstration that white light is actually the product of a colour adhesion process. To test this hypothesis, which held that the prism was not the object that projected the colours, but that the colours were intrinsic to the light itself, Newton carried out two complementary experiments:
In the first one, he added another prism on the opposite side of the first one to develop the experiment in reverse. The result was that the second prism again reunited all the colours, generating white light;
The second of them was Newton's disk: a disk with the seven colors mentioned above, which when rotated rapidly on an axis, gives rise to the perception of the color white.
Within this extensive practical research on light and optics, for which his name is not so well known, but for other theories such as the law of gravitation/gravity, or the theoretical bases of mechanics, Newton laid the foundations of the theory of colors that is still valid today: bodies absorb all colors, except the one perceived, which is the one reflected in the human eye.
All his theories of colour, as well as his research into refraction, reflection and perception of light, were collected in his work “Opticks” published in 1704.
In his studies, Isaac Newton did not make any approximation of colours to variables associated with perception beyond optics. The first studies associated with relevant physical and chemical issues are attributed to the German chemist Wilhelm Ostwald (1853-1932).
