Generally designers have an excellent eye for detail and a skill to differentiate between the slightest color values.  Especially now with 32bit colors being able to be displayed on our monitors the color patellae seems to be endless.  Unfortunately an estimated 9 to 13 percent of males and under one percent of female population have some form of color blindness.

Here are some color blindness definitions found on the web:

• Protanopia means difficulties to distinguish between blue and green colors and also between red and green colors, or no sensitivity to red.
• Deuteranopia is blindness to green.
• Tritanopia is blindness to blue-yellow.

Designers who ignore color blindness can lose or confuse about 10 percent of potential viewers. To avoid this problem Vischeck has a nice tool that will load your website, and display how people with these symptoms will view your site.  From there you can see how clearly your sites is readable and adjust your site.