According to the physical analysis, the colors can be distinguished in elementary or primary (yellow, red, blue) and compounds or secondary (green, purple, orange), which derive from the combination of two primaries.

The extreme terms of the color register are white and black.

             

The primaries:

yellow

red

blue

                         

The secondary:
		green	=				yellow	+			blue
		purple	=				red	+			blue
		orange	=				yellow	+			red

Complementary:
		yellow	< - >			purple
		red	< - >			green
		blue	< - >			orange

The physics of colors

In physics more than color we should talk about color sensation.

In fact, every electromagnetic radiation of wavelength between 0.8 and 0.4 micron gives rise to a sensation of color.

The color of a certain body depends on the spectral distribution of the incident and reflected light. If a body is struck by white light and reflects only the green component, it will appear green. A body that absorbs all the components will appear black.

In addition to the pure physical issue, on the other hand, there is also physiology, that is the reception of color by the human eye , and the consequent reading that makes the brain. For this reason, colors are as important as color combinations.