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Re: Minimum contrast edge case?


From: glen walker
Date: Apr 20, 2018 9:44AM

I'm not seeing how you meet G18. G18 seems to be just explaining in
further detail what 1.4.3 says. It just talks about the contrast ratio and
that your page has to meet it, which is what 1.4.3 says.

If your page does not have sufficient contrast, then it doesn't meet
1.4.3. The *user* needs to have a way (tool) to change the contrast
themself, and the tool itself needs to be discoverable and have sufficient

If you remove the tool because it's distracting, and the page does not have
sufficient contrast, I don't see how that passes.

But maybe I'm misunderstanding your scenario. If the page does *not *have
sufficient contrast and there is *not *a tool to change the contrast, but
the user talks to an admin who can apply a different color scheme so now
the page *does *have sufficient contrast, then you *might* be ok. The
difference seems to be whether the user can change the contrast or if a 3rd
party changes the contrast for them.

If I go back to the W3C statement of: "The basis for determining
conformance to WCAG 2.0 is the success criteria, not the techniques", then
it seems like you'd be ok. The page does have sufficient contrast, after
the admin changed the color scheme. The SC doesn't specify who should set
the color scheme. Just make sure the new color scheme is applied to every


On Fri, Apr 20, 2018 at 6:03 AM, Isabel Holdsworth <
<EMAIL REMOVED> > wrote:

> Thank you Glen for such a comprehensive message. You've given me food
> for thought.
> So we meet G174 by providing the colour preferences tool for most
> scenarios.
> But one of our clients has asked us to remove the tool from their
> instance of our application because they think it will cause
> unnecessary distraction. So in that scenario there's no tool.
> However, it still meets G18 in that if a user specifies that they need
> a conformant colour scheme, the client can set the application up to
> display in that scheme.
> So I don't think we can mark this as a 1.4.3 fail unfortunately.
> On 19/04/2018, glen walker < <EMAIL REMOVED> > wrote:
> > G18 is a "sufficient technique", and while the definition of a
> "sufficient
> > technique" says "If you use the sufficient techniques for a given
> criterion
> > correctly and it is accessibility-supported for your users, you can be
> > confident that you met the success criterion
> > <https://www.w3.org/WAI/GL/2016/WD-UNDERSTANDING-WCAG20-
> 20160105/understanding-techniques.html#ut-understanding-techniques-
> sufficient-head>",
> > it also says "The basis for determining conformance to WCAG 2.0 is the
> > success criteria, not the techniques
> > <https://www.w3.org/WAI/WCAG20/quickref/20160105/#about-techs>".
> >
> > In your particular case, I'm not sure G18 applies to your situation. It
> > sounds more like G174: Providing a control with a sufficient contrast
> ratio
> > that allows users to switch to a presentation that uses sufficient
> contrast
> > <http://www.w3.org/WAI/GL/2016/WD-WCAG20-TECHS-20160105/G174>;.
> >
> > If you allow the color scheme to change *and* the tool that lets you make
> > that change is accessible (including meeting the color contrast ratio),
> > then you're ok. If the tool itself is hidden, then the tool would seem
> to
> > fail WCAG, which means your page does *not* meet 1.4.3. But we'd need
> more
> > information on what you mean by "hidden". Is it visually hidden such as
> > display:none? Is it hidden because it's covered up by another object?
> Is
> > it hidden because it's in an expand/collapse section?
> >
> > Separate from the tool being hidden, you mention the color preferences
> are
> > predefined. That in itself is more of a usability issue and not an
> > accessibility issue. If the predetermined colors meet 1.4.3, then you're
> > ok. If you don't like the colors, that's a design decision.
> >
> > Glen
> >
> > On Thu, Apr 19, 2018 at 3:03 AM, Isabel Holdsworth <
> > <EMAIL REMOVED> > wrote:
> >
> >> Apologies but here's another "does this fail WCAG2" question? I really
> >> appreciate you guys' time and wisdom in answering these, and hopefully
> >> it'll clarify things for others as well.
> >>
> >> I'm working on a web application that fails 1.4.3 (minimum contrast).
> >> To get around this, they provide a tool that allows users to choose
> >> from a whole host of colour schemes, some of which are conformant.
> >>
> >> But in one particular scenario, the tool is hidden and each user's
> >> colour preference is predefined and set at supervisor level and can't
> >> be changed by the user.
> >>
> >> It's frustrating that they've taken the ability to choose a colour
> >> scheme away from the user, but I guess their alternative still passes
> >> under sufficient technique G18 (
> >> https://www.w3.org/TR/WCAG20-TECHS/G18.html ).
> >>
> >> I think I've just answered my own question, but I'd really appreciate
> >> your thoughts.
> >> > >> > >> > >> > >>
> > > > > > > > > >
> > > > >