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Re: high contrast and background images

From: Harry Loots <harry.loots@ieee.org>
Date: Thu, 24 Jun 2010 10:02:36 +0100
Message-ID: <AANLkTinksx6i8r78n4_MiMemqrEwAaQPpbV56Dk-j37R@mail.gmail.com>
To: w3c-wai-ig@w3.org
Just use common sense. If the image provides the user with essential
'content', 'context', 'instructions', 'function', 'visual instructions',
etc... then provide alt text (unless the purpose of the image is already
described in the content - e.g.: a magnifying glass suggesting 'search' next
to a search box which already contains the word 'search' should not have
alt="search" because that will be read as search search by AT devices). If
the image provides background mood, or sensory stimulus, by all means
provide description to enable AT users to 'feel' what you are trying to put
across with your image, but unless it will alter the context or meaning of
the content if you do not provide an 'alt' equivalent, then a null
description is as valid a 'description' as a description containing 1 or 10
or 20 words... (oh and PS! use alt=" " - note space - instead of alt=""
because the lack of space between inverted commas may cause adjacent words
to be concatenated).
Kind regards
Harry



On Thu, Jun 24, 2010 at 3:13 AM, Chris Reeve <chrisreeve15@yahoo.com> wrote:

> I want Shawn's Henrys opinion or Judy Brewer's opinion on this subject.
>
> We are going in circles.
>
>  ------------------------------
> *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 21, 2010 12:36:52 PM
> *Subject:* RE: high contrast and background images
>
> > 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.
>
> I believe background images are fine if there is text alternative, which
> here is different than "alt" text since there is no such attribute for
> background image.
>
> As a side note, most image replacement techniques (the use of a background
> image with alternative text) are better than using <img> elements with "alt"
> text when it comes to copying content in a browser (as most of them will
> ignore "alt" text).
>
> --
> 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 Chris Reeve
> Sent: Sunday, June 20, 2010 10:33 PM
> To: ng@tjkdesign.com; Jonathan Avila; w3c-wai-ig@w3.org
> Subject: Re: high contrast and background images
>
> 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 Thursday, 24 June 2010 09:03:10 GMT

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