For example, asking users to click the red button is not useful if they can't distinguish the red button from other buttons on the screen. The Web page needs to provide another way of making the information available. An image with insufficient foreground and background color contrast will cause problems for some users. An image containing light text on a dark background or dark text on a light background would provide good contrast. Most graphical browsers allow users to override the color of text on the Web page, but users have no control over the color or contrast of images that contain text.
Users can adjust the colors for their links in their browsers.
This checkpoint also does not apply to using color to show where a user is on a navigation bar or within a Web site. Color as additional information is acceptable. The following techniques are the minimum required to meet Checkpoint 12 from the IBM Web Accessibility Checklist . When color is used to convey important information, also use context and markup to convey the same information. For example, you could use an ordered list to identify the item in a list that is also highlighted with color.