
Designers may use any color, not just the 216 Web safe colors.
Whenever possible create color using CSS code not images.
This site which records Browser Display Statistics will help you understand what the screen display is for users.
Visit the Color blindness filter site to see what your site looks like to someone who is color blind
http://colorfilter.wickline.org/
To test the contrast of your text and background use this plug in
Color Analyser - download and install into Firefox to run color tests on Web pages directly within Firefox. Use Luminosity Contrast Ratio
For an extensive