Re: F24 - contrast

Firefox and ie (and perhaps others) allow the user to override css colors
AND bg images - so does that mean that to fulfill the criterion an author
would simply have to use a technology which works in modern browsers? (even
if the css colors failed the contrast ratio) - essentially saying that we
don't have to check contrast on web pages anymore


On Wed, Dec 11, 2013 at 8:39 PM, Ramón Corominas
<rcorominas@technosite.es>wrote:

> Hi, David and all,
>
> Windows high contrast mode changes any foreground colour to the selected
> "automatic" text and any background colour to the selected automatic
> background colour (remember that Windows has different high contrast modes,
> not all of them use dark backgrounds).
>
> In any case, links are not changed to the automatic foreground colour, but
> to the default link text, which sometimes can provoke difficulties.
> Nevertheless, most users of high contrast that I know also change this link
> colour to meet their needs, either in the operating system or in the
> browser itself (browsers usually have an option to override system colours).
>
> However, in technologies different from HTML, colours are not managed the
> same, and for example Word 2010 changes foreground colours to "automatic",
> but leave background colours as defined by the author, which in many cases
> provoke "white over light gray"; in addition, I think Adobe Reader does not
> change any colour unless the reflow option is used.
>
> So, if the Failure only applies to HTML, then it should probably be
> removed, but if it applies to any technology, it is still valid.
>
> Regards,
> Ramón.
>
>
> David wrote:
>
> > The history of this is to enable users to *switch* colours (black to
> > white and vice versa) without the hard coded colours preventing then
> > change... so it black switches to white in the background but the
> > foreground doesn’t switch then you have black text on black
> > background... this is one of those success criteria that we will want to
> > look closely at, because as far as I can tell AT that switches colours
> > such as zoomtext will override even hard coded colours and successfully
> > make the change, We would have to check Windows high contrast mode, but
> > I think it does the same thing... so I question whether we should
> > continue to fail it...
> >
> >
> >>
> >> is F24 - http://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/F24
> >>
> >> a failure even if the actual contrast meets the minimum contrast
> >> requirement ratio? In other words, if an author were to specify black
> >> text color in css (and left the default background-color of say white)
> >> where the ratio meets the success criterion de facto, would this still
> >> fail since no bgcolor was specified in the css (because the user could
> >> run into problems if he did choose a different default background color
> >> in his browser settings)?
>
>
>
>
>
>