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Re: high contrast and background images

From: Chris Reeve <chrisreeve15@yahoo.com>
Date: Sun, 20 Jun 2010 22:32:36 -0700 (PDT)
Message-ID: <610062.2055.qm@web46105.mail.sp1.yahoo.com>
To: ng@tjkdesign.com, Jonathan Avila <jon.avila@ssbbartgroup.com>, w3c-wai-ig@w3.org
I learned that it is impossible to have alt tags when implemeting a background image. My issue is not about the high contrast. It is about the bakckground image. Since H67 is a technique to allow for images that can be avoided by screen readers, here is my suggested test. Put the image on the server. If the image should be ignored by the screen reader, use empty alt tags. Those which are ignored on the previous test should than be implemented as a background-image.

If the image is important to the site owner, that removal is out of the question, than an alt tags is required. Therefore, the background-image usage is out of the question because background images cannot satisfy the alt tag requirements. 



________________________________
From: Thierry Koblentz <ng@tjkdesign.com>
To: Chris Reeve <chrisreeve15@yahoo.com>; Jonathan Avila <jon.avila@ssbbartgroup.com>; w3c-wai-ig@w3.org
Sent: Mon, June 14, 2010 9:10:49 PM
Subject: RE: high contrast and background images


H67 is related to decorative images, so high-contrast settings would not be an issue.
As a side note, there is no such thing as alt text for background images, and H67 does not say to not use alt, it says to use it with a null value (“”).
 
--
Regards,
Thierry
www.tjkdesign.com | www.ez-css.org | @thierrykoblentz
 
From:Chris Reeve [mailto:chrisreeve15@yahoo.com] 
Sent: Monday, June 14, 2010 5:06 PM
To: ng@tjkdesign.com; Jonathan Avila; w3c-wai-ig@w3.org
Subject: Re: high contrast and background images
 
Another possibility I thought of is to choose a background image that can satisfy http://www.w3.org/TR/2008/NOTE-WCAG20-TECHS-20081211/H67
If the chosen background image satisfies H67, than there would not be any need for the alt tag.
 

________________________________

From:Thierry Koblentz <ng@tjkdesign.com>
To: Jonathan Avila <jon.avila@ssbbartgroup.com>; w3c-wai-ig@w3.org
Sent: Mon, June 14, 2010 3:51:08 PM
Subject: RE: high contrast and background images

> The technique developers need to use will allow this text to appear in
place of the background image when high contrast is used.

A better approach would be to *not* use a technique that relies on
background-image to avoid losing these images when users switch to high
contrast styles sheets. 

For example, a technique like this one should make this a non-issue:

http://tjkdesign.com/articles/how-to_use_sprites_with_my_Image_Replacement_t
echnique.asp

--
Regards,
Thierry
www.tjkdesign.com | www.ez-css.org | @thierrykoblentz

From: w3c-wai-ig-request@w3.org [mailto:w3c-wai-ig-request@w3.org] On Behalf
Of Jonathan Avila
Sent: Monday, June 14, 2010 11:19 AM
To: w3c-wai-ig@w3.org
Subject: RE: high contrast and background images

Chris Reeve Wrote:
“Cindy, I do not know enough about what Roger is talking about. But I do
know, that when you use a background image; it is impossible to use an alt
tag. Therefore by default; all alt background images will fail 1.1.1
 
This information came to me from an accessibility seminar I attended last
year.”
 
CSS background sprites are used to reduce the number of image files
transferred and thus speed of page load times for many users.  A small
portion of a background image can more easily be shown in a certain element
and thus a single background image can contain many of the images to be
shown on the page. There are many good techniques out there to couple text
and alternative text to the area where the background image appears.  The
technique developers need to use will allow this text to appear in place of
the background image when high contrast is used.
 
Jonathan


      
Received on Monday, 21 June 2010 05:33:10 GMT

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