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Update term "contrast ratio" for SC 1.4.11 #1018

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Update term "contrast ratio" for SC 1.4.11 #1018

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Update contrast-ratio.html
Jan 26, 2020
67cef5c
Merge branch 'main' into contrast
patrickhlauke May 5, 2025
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14 changes: 7 additions & 7 deletions guidelines/terms/20/contrast-ratio.html
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Expand Up @@ -15,20 +15,20 @@

<p class="note">Contrast ratios can range from 1 to 21 (commonly written 1:1 to 21:1).</p>

<p class="note">Because authors do not have control over user settings as to how text is rendered
(for example font smoothing or anti-aliasing), the contrast ratio for text can be
<p class="note">Because authors do not have control over user settings as to how text and non-text content is rendered
(for example font smoothing or anti-aliasing), the contrast ratio can be
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(for example font smoothing or anti-aliasing), the contrast ratio can be
(for example font smoothing or anti-aliasing), the contrast ratio should be

evaluated with anti-aliasing turned off.
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while the sentiment/idea is valid - that it's not just text but also non-text content, it's not possible to turn off anti-aliaising for things like SVG or CSS lines etc. And even for text, it's not always possible - depending on OS or user agent - to turn it off even for text rendering.

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instead of just "with anti-aliasing turned off", this may need to be expanded to something like

Suggested change
evaluated with anti-aliasing turned off.
evaluated with anti-aliasing turned off or ignored.

</p>

<p class="note">For the purpose of Success Criteria 1.4.3 and 1.4.6, contrast is measured with respect
to the specified background over which the text is rendered in normal usage. If no
background color is specified, then white is assumed.
to the specified background over which the content is rendered in normal usage. If no
background color is specified, then white is assumed. If no
foreground color is specified, then black is assumed.
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as 1.4.3 and 1.4.6 are specifically about text, there's no sense here changing things to be more generic

</p>

<p class="note">Background color is the specified color of content over which the text is to be rendered
in normal usage. It is a failure if no background color is specified when the text
<p class="note">It is a failure if no background color is specified when the foreground
color is specified, because the user's default background color is unknown and cannot
be evaluated for sufficient contrast. For the same reason, it is a failure if no text
be evaluated for sufficient contrast. For the same reason, it is a failure if no foreground
color is specified when a background color is specified.
</p>

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