CertiGuide to A+ (A+ 4 Real)  9  Chapter 9: Graphic Cards       9  Fundamentals of Computer Graphics: Pixels, Resolution and Color

Fundamentals of Computer Graphics: Pixels, Resolution and Color 1 Memory Use by Images

As most people know, in the computing world colour is defined using red, green and blue values which, when combined together in varying intensities, can produce the full range of colors the human eye can see. Nevertheless, as any 6 year old knows, the "real" primary colors are red, yellow and blue. So what is the difference?

The confusion is caused by the word "color", and the answer lies in the difference between pigment and light. If one was to discuss "color" with a hardware engineer they will most likely say that they can make any "color" required by manipulating red, green and blue light. However, if one discusses "color" with an artist, they will no doubt say that the engineers are wrong and colors are made by mixing red, blue and yellow paints (''pigments''). Just to confuse matters, they are both telling the truth!

Colored light is simply light made up of multiple light waves of different wavelengths. As can be seen when standing under a disco light system for any length of time, different colored lights (wavelengths) can combine to produce further differently colored lights. This works because the light waves are cumulative - they add together to produce a resulting colour. The special properties of red, green and blue light waves are that they contain all the wavelengths needed to produce all the colors the human eye can see. Combining lights in this way is called "additive" blending, which is a term 3D graphics programmers refer to a lot.⁹³

As you have probably guessed, because your monitor emits light (rather than having a little person sitting inside mixing paints together) to display images, the red, green and blue (RGB) system is used.

Fundamentals of Computer Graphics: Pixels, Resolution and Color 1 Memory Use by Images