Fwd: [WebAIM] Contrast and Color Accessibility, Understanding WCAG 2 Contrast and Color Requirements

additional information for our discussion of issue #451

---------- Forwarded message ---------
From: Jared Smith <jared@webaim.org>
Date: Wed, Dec 5, 2018 at 9:05 AM
Subject: Re: [WebAIM] Contrast and Color Accessibility, Understanding WCAG
2 Contrast and Color Requirements
To: WebAIM Discussion List <webaim-forum@list.webaim.org>


Alastair Campbell wrote:

> Take this Android toggle button example:
> https://androidician.files.wordpress.com/2014/09/output_potdse.gif
> (animation warning)
>
> The grey doesn't have to contrast with the blue.

Of course not, because there are several other visual indicators of
state change. But what if color/contrast was the ONLY indication of
state, particularly hover state?

I put together the following page to demonstrate this, and to show
that, if 1.4.11 requires 3:1 contrast between states, this could be
considered rather constraining to button design:

https://webaim.org/temp/1-4-11examples.htm

I'd be happy to hear your opinions on the "Pass or Fail?" scenarios.
It's still not clear to me what WCAG requires here.

> We did some analysis of examples, including from some
> of the common pattarn libraries:
> https://alastairc.ac/tests/wcag21-examples/non-text-contrast.html

I don't think anything here examines the specific scenarios I'm
discussing - where color/contrast alone is changed on hover. Your
suggestion that the change in cursor on hover is sufficient to meet
1.4.11 is interesting. This alone suggests that you believe 1.4.11
must provide state differentiation. Cursor change, however, would not
be applicable to buttons which do not (and, arguably, should not) do
so on hover.

> Indeed, I'm afraid we have a slight backlog of issues in this area:
>
https://github.com/w3c/wcag/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+1.4.11
>
> I think once we've worked through those it should be clearer, we're
> also trying to get techniques done which should help, but can't do
> everything at once.

When I have some time, I'll add these scenarios and my thoughts to the
logged bugs. I do hope that corrections to the mistakes and ambiguity
in the already-published WCAG materials would be given priority
treatment - I think giving incorrect or ambiguous guidance is more
detrimental than not giving guidance at all.

Thanks!

Jared
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-- 
Jim Allan, Accessibility Coordinator
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9452 http://www.tsbvi.edu/
"We shape our tools and thereafter our tools shape us." McLuhan, 1964