HTML & XHTML Pocket Reference, 4th Edition

Specifying Color

Because color is presentational, it should be specified with Cascading Style Sheets, not HTML attributes. This material is included only for completeness.

In both (X)HTML and CSS, color values may be provided by numeric values or standardized color names.

RGB Values

The most common and precise way to specify a color is by its numeric RGB (red, green, blue) values. Using an image-editing tool such as Adobe Photoshop, you can determine the RGB values (on a scale from 0 to 255) for a selected color. For example:

Red: 212 Green: 232 Blue: 119

These values must be converted to their hexadecimal (base-16) equivalents in order to be used as attribute values. In this example, the previous decimal values are converted to hexadecimal:

Red: D4 Green: E8 Blue: 77

In (X)HTML, these values are provided in a six-character string, preceded by the # symbol, like so:

#D4E877

The underlying syntax is this:

#RRGGBB

where RR stands for the hexadecimal red value, GG stands for the hexadecimal green value, and BB stands for the hexadecimal blue value.

Fortunately, Adobe Photoshop makes the hexadecimal values for colors readily available at the bottom of the color picker next to the # symbol. The hex values can be copied from the color picker and pasted into a style sheet or HTML document.

If you are using an image tool that does not list hexadecimal values, you’ll need to convert decimal to hexadecimal yourself using a hexadecimal calculator. Windows users can find a hexadecimal calculator in the ...