Scientists have discovered that the true primary colors are red, green, and blue. These colors have a basis in the biology of the human eye: there are color receptors, called cones, in the back of the eyeball for each of them.
These cones send signals to the brain, which then interprets the "color." If the brain gets signals from the red and blue cones, it will read the color purple.
| The Real Primary Colors | Versus | The Primary Colors of Art |
|---|---|---|
There is a popular belief that the primary colors are red, yellow, and blue. These colors were traditionally used by artists who mixed paint to achieve different colors.
Computers follow biology and use a mixture of red, green and blue to achieve all the colors you see on the screen.
In tests, scientists found that the human eye can distinguish between no more than 256 shades of a primary color. 0-255 can be expressed in hexadecimal as 0-FF. Thus, a two digit hexadecimal code can be used for each of the three primary colors.
Here's an example of different shades of cyan (equal values for blue and green), with hexadecimal values given on top. The values increase in increments of one, then 2, then 4, then 8, then 16.
Not all computers can correctly display all of the shades below. The first row of colored boxes should appear to be nearly identical to each other, but each box in the last row should be brighter than the one to its left.
| + 1 | 79 | 80 | 81 | 82 |
| + 2 | 84 | 86 | 88 | 8A |
| + 4 | 8E | 92 | 96 | 9A |
| + 8 | A2 | AA | B2 | BA |
| + 16 | CA | DA | EA | FA |
Continue to Part Three, Using Hexadecimal Code to Express Color