At this time, even the cheapest new monitors can support 2²⁴ (16,777,216) colors, which is many more colors than the human eye can decipher. How does the monitor make that many colors?

It is quite simple. The monitor is made of many small dots called pixels. Each pixel is assigned a different color. When many of these pixels are put together, they make an image on the screen that the user can look at. To give you an idea of just how many pixels there are on your monitor, most 15 inch monitors have about 800,000 pixels. Monitors which have a screen size of 17 inches have about 1.3 million pixels, while a typical 19 inch monitor has almost 2 million pixels!

Now back to the colors. Each pixel's color is determined by the intensity of three sources of light. These sources of light are three different colors. They include red, green and blue. Each of the three lights can have 2⁸ or 256 different intensities of the color, going from black to the purest form of each of the colors (for the red light source, an intensity of 0 would be black, while intensity of 255 would be a pure red).

Since each of the three lights can produce 256 different colors, and there are three light sources, the monitor can produce 256³ or 16,777,216 different colors. To give you a visual idea of how the colors are mixed to produce one color that you can see for the pixel, here is a flash presentation you can try out. Move the bars around and click on the change color button to make different colors.

Full Screen

As you can see, there are three light sources or masks. They overlap to make the final color. The color in the middle of all three masks represents the color that the user would see for the specific pixel. The colors in between any two masks represent the color that would be created if only these two masks were mixed together. Note that if you leave all the bars at 0, black is made, while all the bars at 255 would make white.

Now that we know how the color is made by the monitor, it is time to learn how the monitor knows which colors to use. We know that each of the colors can have 256 different intensities (0 to 255). Since eight bits or one byte can also have 256 combinations, we can use one byte to represent the intensity of one of the three masks or sources of light. Since there are three lights, we need three bits or 24 bytes to give the monitor information as to which color each pixel would be. For example, if the monitor got data for a specific pixel which was 00000000 00000000 00000000, it would mean that the red, green and blue masks should have an intensity of 0, making the pixel a pure black. On the other hand, if the monitor got data for a specific pixel which was 11111111 11111111 11111111, it would mean that the red, green and blue masks should have an intensity of 255, making the pixel a pure white.