Theory of Colors

Sir Isaac Newton was the first man to use a wheel to represent colors. His color wheel is comparable to the periodic table of elements in chemistry—it helps us predict what colors can be generated by mixing. Of course, we can do that by simply adding two colors together, but why not have a simpler, easier method to predict the result?

The color wheel has three additive primary colors, and these three colors can be mixed to form every color in the crayon box, just as the human eye (link to vision) detects red, blue and green to distinguish the vast range of shades we see. These three colors occupy three main points on the circle, and opposite to them lie their complementary colors. All the colors of the spectrum have different wavelengths, and according to this, they are placed around the color wheel:

Each spectral color has a specific wavelength of its own—not a combination of wavelengths or colors giving rise to shades we see. Hence, magenta, although complementary to red, is not a spectral color. If red, green and blue are connected with straight lines to their complementary color, six sectors are formed. The colors are placed along the circumference on the basis of complex mathematical calculations that split up the circumference in accordance to wavelength of the colors, but this does not really concern us as it is far beyond our comprehension. Also, the colors get more saturated as you move towards the circumference along the radii of the wheel.

Instead, the color wheel, as stated before, tells us what color we can get by mixing two colors. If you connect the red and the green dot, you will find that the line connecting blue and yellow bisects (or splits into half) the line drawn. The intersection of the lines take place on the “yellow” line, so you may infer that equal amounts of red and green produce yellow. Similarly, if blue is connected to green, the line intersects the “cyan” line; so we know blue and green mixed together will produce cyan.

Colors on the same radial line have the same hue, but as they move outwards they become less saturated. In the same manner, colors on the circumference have the same saturation, but we can tell the difference visibly because they have different hues. A mixture of red with cyan or blue with yellow or green with magenta in equal proportion would all give a colorless mixture, as the center of the circle symbolizes the achromatic (colorless).

Source: library.thinkquest.org