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Re: Color contrast for graphical objects


From: Patrick H. Lauke
Date: Jan 26, 2020 11:42AM

On 26/01/2020 18:10, Colleen Gratzer wrote:
> I am trying to confirm color contrast requirements for graphical objects.
> This WebAIM color checker page at
> https://webaim.org/resources/contrastchecker/ says:
> "WCAG 2.1 requires a contrast ratio of at least 3:1 for graphics and
> user interface components (such as form input borders)."
> But this W3C page
> https://www.w3.org/WAI/GL/low-vision-a11y-tf/wiki/Informational_Graphic_Contrast_(Minimum)#Notes_on_how_the_contrast_and_thickness_were_derived
> says:
> "Graphics that are very thin are harder to perceive, therefore have a
> higher contrast requirement of 4.5:1. Graphics that are thicker or are
> solid shapes have a lower requirement of 3:1."
> Is it just that the WebAIM page does not go into detail about this, and
> that, yes, form field borders, buttons and icons that are thin do in
> fact need to meet a 4.5:1 ratio?

That wiki page is not the official normative specification. It was last
updated in Feb 2017, before WCAG 2.1's final version. The normative
requirement for SC 1.4.11 is 3:1. And even in the understanding document
there's no mention of any stricter ratio requirements.

Patrick H. Lauke

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