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Re: [css3-images] [Fwd: RE: CSS Image Values and Replaced Content Module Level 3 - very brief review]

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Wed, 14 Mar 2012 16:00:21 -0700
Message-ID: <CAAWBYDCCnwVOwCYtSLJ-3x3WZ1rAKu5ej93_Rv+-u1uKQBKbLw@mail.gmail.com>
To: James Nurthen <james.nurthen@oracle.com>
Cc: Michael Cooper <cooper@w3.org>, CSS WG <www-style@w3.org>, WAI PFWG <w3c-wai-pf@w3.org>, WAI XTech <wai-xtech@w3.org>, WAI Liaison <wai-liaison@w3.org>
On Wed, Mar 14, 2012 at 3:34 PM, James Nurthen <james.nurthen@oracle.com> wrote:
> On 3/14/2012 2:31 PM, Tab Atkins Jr. wrote:
>>>
>>> 4. Gradients
>>>
>>> It should probably be stated that gradients can cause subtle issues with
>>> maintaining a sufficient luminosity contrast ratio between the text and
>>> its
>>> background. (an informative note about making sure to meet WCAG2 1.4.3 is
>>> probably good)
>>
>> How is this any different from the generic situation with background
>> colors/images and contrast?  I haven't added anything about this.
>
> The biggest difference between generic colors and the other scenarios
> (images / gradients / rgba colors) is the difficulty in measuring the ratio
> to determine if you have sufficient contrast. With rgb colors it is trivial
> to determine if you have sufficient contrast. With the others there is no
> automated way to measure the ratio.

My point was that this advice seems to be generic to all images, and
has nothing to do with gradients in particular.  If it's appropriate
to add this disclaimer here, then we should also add it to element(),
and to every other method we come up with for producing images behind
text in all of CSS.

In other words, I think this sort of warning is already covered by the
generic "make sure your text and background have sufficient contrast"
advice from WCAG.

~TJ
Received on Wednesday, 14 March 2012 23:01:11 GMT

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