Chapter 8. Color Names and Values
You may specify the color value as a six-digit hexadecimal number that represents the red, green, and blue (RGB) components of the color. The first two digits correspond to the red component of the color, the next two to the green component, and the last two to the blue component. A value of 00 corresponds to the component being completely off; a value of FF (255) corresponds to the component being completely on. Thus, bright red is FF0000, bright green is 00FF00, and bright blue is 0000FF. Other primary colors are mixtures of two components, such as yellow (FFFF00), magenta (FF00FF), and cyan (00FFFF). White (FFFFFF) and black (000000) are also easy to figure out.
You use these values in a tag by replacing the color with the RGB triple, preceded by a hash (#) symbol. To make all visited links display as magenta, use this body tag:
<body vlink="#FF00FF" >
Determining the hexadecimal value for more esoteric colors like "papaya whip" or "navajo white" is very difficult. You can go crazy trying to adjust the RGB triple for a color to get the shade just right, especially when each adjustment requires loading a document into your browser to view the result.
To make life easier, the HTML 4.0 standard defines 16 standard color names that can be used anywhere a numeric color value can be used. You can make all visited links in the display magenta with the following attribute for the body tag:
<body vlink="magenta" >
The color names and RGB values defined in the HTML standard are:
Colors marked with an asterisk (*) represent a family of colors numbered one through four. Thus, there are actually four variants of blue, named blue1, blue2, blue3, and blue4, along with plain old blue. Blue1 is the lightest of the four; blue4 the darkest. The unnumbered color name is the same color as the first; thus, blue and blue1 are identical.
Finally, if all that isn't enough, there are 100 variants of gray (and grey) numbered 1 through 100. Gray1 is the darkest, gray100 is the lightest, and gray is very close to gray75.
The extended color names are:
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