1 COLOR PHYSICS

In 1676, Sir Isaac Newton, using a three-sided prism, laid out the white sunlight on the color spectrum. A similar spectrum contained all colors except purple.

Newton put his experience as follows (Fig. 1). Sunlight passed through a narrow slit and fell on a prism. In a prism, a white beam was exfoliated into separate spectral colors. Decomposed in this way, it was then sent to the screen where the spectrum image appeared. The continuous color ribbon began with red and through orange, yellow, green, blue ended in purple. If this image was then passed through a collecting lens, the combination of all colors again gave a white color.

These colors are obtained from the sunbeam using refraction. There are other physical ways of forming color, for example, related to the processes of interference, diffraction, polarization and fluorescence.

If we divide the spectrum into two parts, for example, into red-orange-yellow and green-blue-violet, and we collect each of these groups with a special lens, we will end up with two mixed colors, which in turn will also give us white color. .

Two colors, the combination of which gives white color, are called complementary colors.

If we remove one color from the spectrum, for example, green, and collect the remaining colors — red, orange, yellow, blue, and purple — through a lens, then the mixed color we received will turn out to be red, that is, an additional color to the green we removed. If we remove the yellow color, the remaining colors — red, orange, green, blue, and purple — will give us a purple color, that is, a color that is complementary to yellow.

Each color is optional with respect to a mixture of all the other colors in the spectrum.

In mixed color, we can not see its individual components. In this regard, the eye is different from the musical ear, which can distinguish any of the sounds of the chord.

Different colors are created by light waves, which represent a certain kind of electromagnetic energy.

The human eye can perceive light only at wavelengths from 400 to 700 millimicron:

• 1 micron or 1μ = 1/1000 mm = 1/1000000 m.
• 1 millimicron or 1mμ = 1/1000000 mm.

The wavelength corresponding to the individual colors of the spectrum, and the corresponding frequencies (number of oscillations per second) for each spectral color have the following characteristics:

The frequency ratio of red and purple is approximately 1: 2, that is, the same as in a musical octave.

Each color of the spectrum is characterized by its wavelength, that is, it can be absolutely accurately defined by the wavelength or oscillation frequency. Light waves themselves have no color. Color occurs only when these waves are perceived by the human eye and brain. How he recognizes these waves is still completely unknown. We only know that different colors result from quantitative differences in photosensitivity.

It remains to investigate the important question about the body color of objects. If we, for example, put a filter that passes red and a filter that passes green, in front of the arc lamp, then both filters will give a black color or darkness. The red color absorbs all the rays of the spectrum, except the rays in the interval that corresponds to the red color, and the green filter retains all colors except green. Thus, not a single ray is let through, and we get darkness. The colors absorbed in a physical experiment are also called subtracted.

The color of objects occurs mainly in the process of absorbing waves. A red vessel looks red because it absorbs all other colors of the light beam and reflects only red.

When we say: “this cup is red,” then we actually mean that the molecular composition of the cup's surface is such that it absorbs all the light rays, except the red ones. The cup itself has no color, the color is created when it is illuminated.

If red paper (the surface that absorbs all rays except red) is illuminated with green light, then the paper will appear black to us, because green does not contain rays that correspond to red, which could be reflected by our paper.

All paints are pigment or material. These are absorbent (absorbing) paints, and when mixing them should be guided by the rules of subtraction. When additional colors or combinations containing the three primary colors — yellow, red, and blue — are mixed in a certain proportion, the result will be black, while a similar mixture of non-real colors, obtained in a Newtonian experiment with a prism, results in a white color, since here the union of colors is based on the principle of addition, not subtraction.