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RE: background-image in CSS

From: Jason Megginson <jason@bartsite.com>
Date: Thu, 17 Jan 2002 15:27:40 -0500
To: "'Kynn Bartlett'" <kynn-edapta@idyllmtn.com>, "'Jon Hanna'" <jon@spinsol.com>, <w3c-wai-ig@w3.org>
Message-ID: <00ca01c19f95$69ef04a0$fe1ba8c0@jmegginson>
>>You know that you are still within the same department if you see that
>>color displayed; if the color changes, you're on a different part of
the >>site.
>>
>>This is clearly conveying information via colors and backgrounds.
There is >>obviously content conveyed there!

I'm going to have to disagree, Kynn.  Color in your case serves no
purpose in conveying information, only layout and organization is made
by the use of these colors.  Many (and I'm speaking by experience)
low-vision users turn off colors associated with style sheets for better
contrast, so as a means of information, it doesn't and shouldn't matter
whether the pages are "color coded".  

If color here is in fact a means of information as you say, disabling
style sheets would cause the page to be inaccessible, a violation of
sorts, and I would think of changing your design.
J



-----Original Message-----
From: w3c-wai-ig-request@w3.org [mailto:w3c-wai-ig-request@w3.org] On
Behalf Of Kynn Bartlett
Sent: Thursday, January 17, 2002 2:39 PM
To: Jon Hanna; w3c-wai-ig@w3.org
Subject: RE: background-image in CSS

At 5:19 PM +0000 1/17/02, Jon Hanna wrote:
>If the image does convey *any* information (beyond the authors' taste
>in background images) then it's content and it should be included in
>the HTML as such, not used as a background.

It's important to be careful what we mean about "any content", if
we are talking about content then we need to focus on that CONTENT
rather than a particular mode of presenting that content.

Here's what I mean.

My wife designed the City of Fullerton web site.  Each part of the
site corresponds to a specific department with City Hall.  These
departments each have a color scheme assigned to them.  The
backgrounds (of the navbar etc.) are color coded.  You know that
you are still within the same department if you see that color
displayed; if the color changes, you're on a different part of
the site.

This is clearly conveying information via colors and backgrounds.
There is obviously content conveyed there!

Because we want to encourage effective use of the visual medium,
this is something that we should applaud.  It is good and proper,
and an aid to understanding the site.

Note that it does not violate any WCAG or 508 checkpoints,
because the information is also available via other means --
for example, the section of the site is clearly shown in a
"breadcrumbs"-style hierarchy locator.

A background image could and should be used in the same way;
for example, a watermark style background image on the left hand
side of the page, under the navigation bar, may depict a Model
A Ford on a Model A Ford web site.  This is effective visual
communication, and content is clearly being conveyed via the
background image.

However, it does not have to be included in the markup _if_
the purpose of the background (or color, or whatever) is
to _reinforce_ the content which is already available in some
other manner.  As long as the information is in the markup,
then using it as a background is perfectly fine and in fact
encourageable.

So I would rewrite your statement to say:

      If the image does convey *any* information, then that
      content should be included in the HTML in addition to
      being used as a background.

The problem I had with your original statement was that it
focused on the background image rather than on the content
conveyed by it.

--Kynn

-- 
Kynn Bartlett <kynn@idyllmtn.com>                 http://kynn.com
Chief Technologist, Idyll Mountain            http://idyllmtn.com
Web Accessibility Expert-for-hire          http://kynn.com/resume
January Web Accessibility eCourse           http://kynn.com/+d201
Forthcoming: Teach Yourself CSS in 24 Hours
Received on Thursday, 17 January 2002 15:26:09 GMT

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