Colors or RGB
Colors in a computer program are represented by combining 3 "pigments." These pigments are red, green, and blue (which contrasts with the "primary" colors we are used to as children). By combining some amount of red, some amount of green, and some amount of blue, any (displayable) color can be achieved.

RGB Colors
All colors on a computer are made up by combining the light from three colors (red, blue, and green). Black is [0,0,0], and White is [255, 255, 255]; Gray is any [x,x,x] where all the numbers are the same.

The maximum value of each of the colors is 255. The minimum value is 0.

Colors are almost always written with the red value first, the green value second, and the blue value third. Memorize "RGB," and you will remember the ordering.

Here are some examples:

White = [255, 255, 255]
Black = [0, 0, 0]
A "perfect" blue = [0,0,255]
A "prefect" red = [255, 0, 0].
A "middle" Gray = [122, 122, 122]
Hex Notation
For historic reasons, colors are often written in HEX, which is base 16 (contrast this with decimal, which is base 10). The digits in HEX are 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F (where A-F represent 10 through 15). The largest available color is FF (which means 15 * 16 + 15) or 255. The smallest available color is 00 (which means 0 * 16 + 0) or 0.