One of the core principles of access for people with disabilities is that information should be understood even if the user can't see color.
Mac-using Web developers can test their pages for color dependence by viewing pages in grayscale. Here's how you do that in Mac OS X:
- Open System Preferences and select the Universal Access panel
- Select the Seeing tab.
- Click on "Set Display to Grayscale." Ta da!
- View the pages in Safari or another browser. Change back by repeating these same steps to reset the display.
This technique can also be used by application developers to ensure their apps meet Apple's Human Interface guidelines for color dependence. The Universal Access settings are actually quite useful beyond simply enabling access by people with disabilities.

