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WCAG 2.0 Released

Filed under: Accessibility, News

The Web Content Accessibility Guidelines (WCAG) 2.0 were finally published yesterday and are officially described as applying to “more advanced technologies“. The new guidelines are also supposed to be easier to use and understand (although I’d advise you keep paracetamol and plenty of coffee to hand) and are designed to be more precisely testable via automated testing and human evaluation.

The good news is that most web sites that already conform to WCAG 1.0 should not require significant changes in order to conform to WCAG 2.0. And some may not need any changes — presumably those sites that significantly exceeded Level AA under WCAG 1.0.

However, like everything new, WCAG2.0 is going to take some getting used to…

WCAG 1.0 was based around guidelines & checkpoints (priority 1, 2, or 3). The basis for determining conformance to WCAG 1.0 were the checkpoints. WCAG 2.0, on the other hand, is organised around 4 “Principles of Web Accessibility” which dictate that web content must be:

  1. Perceivable — Information and user interface components must be presentable to users in ways they can perceive.
  2. Operable — User interface components and navigation must be operable.
  3. Understandable — Information and the operation of user interface must be understandable.
  4. Robust — Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies

POUR: Perceivable, Operable, Understandable, Robust.

Each Principle has its guidelines (there are 12 guidelines in total) and each guideline has a number of testable success criteria at Level A, AA, or AAA . The basis for determining conformance to WCAG 2.0 are these success criteria.

An Example

Colour contrast issues are covered by Principle 1 (Perceivable):

“Guideline 1.4: Distinguishable: Make it easier for users to see and hear content including separating foreground from background.”

Success Criterion 1.4.3 [Contrast (Minimum)]

The visual presentation of text and images of text has a contrast ratio of at least 4.5:1 for normal text and at least 3:1 for large-scale text (Level AA).

Success Criterion 1.4.6 [Contrast (Enhanced)]

The visual presentation of text and images of text has a contrast ratio of at least 7:1 for normal text and at least 4.5:1 for large-scale text (Level AAA).

In this context, “large-scale text” is defined as least 18 point for normal weight text and at least 14 point for bold text *.

So, broadly speaking, WCAG 2.0 Success Criteria 1.4.3 and 1.4.6 are comparable to WCAG 1.0 Checkpoint 2.2. Except that we can now also take into account the size and weight of the text used — issues that WCAG 1.0 failed to address. WCAG 2.0 also exempts Logotypes (text that is part of a logo or brand name) from even the minimum contrast requirements — which should remove a major bone of contention between web development and marketing teams.

To further ease the pain of transition, W3C has provided a Comparison of WCAG 1.0 Checkpoints to WCAG 2.0. Happy reading!

*Addendum: For those of us who specify text in ems, I’ve calculated that 18 point text equates to around 1.64em whilst 14 point text is around 1.27em. More on the basis for these figures later. Back

Published: December 12th 2008