Text is less than 18 point if not bold and less than 14 point if bold (Situation A)
Text is at least 18 point if not bold and at least 14 point if bold (Situation B)
No minimum contrast requirement for text or images of text:
that are part of an inactive user interface component
that are pure decoration
that are not visible to anyone,
that are part of a picture that contains significant other visual content
that is part of a logo or brand name
Failures
[ ] F24: Specifying foreground colors without specifying background colors or vice versa (#187 )
[ ] F83: Using background images that do not provide sufficient contrast with foreground text (or images of text)
Techniques
[ ] G148: Not specifying background color, not specifying text color, and not using technology features that change those defaults (see F24 #187)
[ ] G174: Providing a control with a sufficient contrast ratio that allows users to switch to a presentation that uses sufficient contrast
[x] G18: Ensuring that a contrast ratio of at least 4.5:1 exists between text (and images of text) and background behind the text for situation A AND G145: Ensuring that a contrast ratio of at least 3:1 exists between text (and images of text) and background behind the text for situation B ( #71 )
Relationship between techniques and Failures
G18 and G145 are exactly the same, only the ratio differs
G18 is also used on AAA level, but then for situation B.
F24 is counterpart for G148
F83 is part of the check in G18+G145, but as images can't change their contrast with a control or backgorund css it's a real failure and G174 or G148 can't help that.
G18 + G145 is the most common technology, but if they fail, we can't fail this success criterion if we don't check for G148 (easy) or G174 (difficult as we should detect a control)
http://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-contrast.html The visual presentation of text and images of text has a contrast ratio of at least 4.5:1
Applicability
Always
Selector
Text parts:
No minimum contrast requirement for text or images of text:
Failures
Techniques
Relationship between techniques and Failures