Colors are defined using a hexadecimal notation for the combination of red, green, and blue color values (RGB). The lowest value that can be given to one light source is 0 (hex #00). The highest value is 255 (hex #FF). This table shows the result of combining red, green, and blue:
A collection of color names is supported by most browsers. To view a table of color names that are supported by most browsers visit this web page: http://profdevtrain.austincc.edu/html/ color_names.htm
Web Safe Colors
A few years ago, when most computers supported only 256 different colors, a list of 216 Web Safe Colors was suggested as a Web standard. The reason for this was that the Microsoft and Mac operating system used 40 different "reserved" fixed system colors (about 20 each). This 216 cross platform web safe color palette was originally created to ensure that all computers would display all colors correctly when running a 256 color palette. To view the 216 Cross Platform Colors visit this web page: http://profdevtrain.austincc.edu/html/216.html
16 Million Different Colors
The combination of Red, Green and Blue values from 0 to 255 gives a total of more than 16 million different colors to play with (256 x 256 x 256). Most modern monitors are capable of displaying at least 16,384 different colors. To assist you in using color schemes, check out http://wellstyled.com/tools/colorscheme2/index-en.html. This site lets you test different color schemes for page backgrounds, text and links.