2.1.2 Meeting the guidelines for the first principle, perceivable

The following are some of the points you will want to take into consideration when creating web content and websites that meet the Web Content Accessibility Guidelines 2.0 for the first principle, perceivable.

Level A Accessibility requirements:

  • Important graphical content must be also described with text so that text-to-speech systems can provide this alternative content to people who cannot see the images. Refer also to Example 1.
  • Content should be created so that it will not lose its basic structure or meaning when displayed on different web or assistive devices, such as Braille, speech recognition software and text telephones.
  • Do not use colour, shape, location or sound as the sole method of providing instructions to the user. Directions such as 'click on the red link', 'press the stop-sign button', 'the link on the bottom left of the page', or 'when you hear the tone, go to the next page' are examples of inaccessible design.
  • Content should not be difficult to distinguish from the background or foreground because of poor choices of colour or images. Refer also to Example 2.

Level AA Accessibility requirements:

  • Websites and their content should generally be at a contrast ratio of 4:5:1. A free and easy tool to check your contrast is the Colour Contrast Analyser available for Windows or Mac.
  • Use relative units (e.g. 0.5 em) and percentages rather than specific sizes (e.g. 12 pt) so pages are readable and functional when the text size is enlarged up to at least 200%.

Audio and Video - Time-Based Media (WCAG 2.0 Guideline 1.2)

One of the more complex requirements is how to make audio and video content accessible.