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Re: Specifying foreground and background colors

From: Peter Verhoeven <pav@oce.nl>
Date: Wed, 14 Jun 2000 09:00:27 +0200
Message-Id: <4.3.1.1.20000614081934.00b2c720@pophost.oce.nl>
To: Wendy A Chisholm <wendy@w3.org>, Charles McCathieNevile <charles@w3.org>
Cc: w3c-wai-gl@w3.org, w3c-wai-ua@w3.org, w3c-wai-er-ig@w3.org
Hi Wendy,

At 21:07 13-06-2000 -0400, Wendy A Chisholm wrote:

>My main question is not "should we include this as a technique."
>
>Rather, my question is, "what is the accessibility rationale for this 
>technique."

Answer, bad color contrast is the #1 accessibility problem for people with 
low vision. In some browsers the user can set a prefered color combination, 
but on a lot of web pages this doesn't help at all, because of the use of 
text images.

>  I did not see any, thus did not include any in my proposal.
>
>I think the rationale is "good design."  Regardless of whether I choose a 
>high-contrast background and foreground color combination (white and dark 
>red), if the user only selects a foreground color (white) current user 
>agents will not select a high contrast background color.

You are right at this point. A lot of color problems are caused by the 
browser. I see a lot of pages where only the background and or text color 
is defined by the designer not the link, vlink and alink colors.
But the reason that most people do not use default colors is because of 
text images.

>  They will display the author set background color (white) and the user 
> set foreground color (white).  The user will have to select a foreground 
> color as well.

In my opinion if the author sets any color he or she must set all colors. 
On a lot of web pages the background "color" is an image. The user default 
settings do not work at all on these pages.
This problem could also be solved by the possibility to disable background 
images in the browser.


>  In some browsers, the user could select "high-contrast mode" where the 
> browser selects both the foreground and background colors.  For example, 
> yellow text on a black background.

Only Opera has some good low vision options in its browser. But this 
browser is used by only 0.2%  of the Internet population, because it is not 
free and doesn't support all Internet languages like Java.
In Internet Explorer and Netscape there are only some limited low vision 
options available and options that disable things like loading images or 
Java aplets. These kind of options have nothing to do with accessibility 
only increases the inaccessibility if you select them.

>>Maybe we should ask the ER or UA groups to look in more detail at the issue
>>of ensuring contrast? Most User Agents allow a choice of colours, although
>>most do not automatically pick a contrasting colour where there is a conflict
>>or semi-specified colour scheme.
>
>I think this is a UA issue and have CC'ed the UA working group.  Chris 
>Ridpath recently published results of a color study, so I have CC'ed ER as 
>well.  Refer to the techniques for Checkpoint 2.2 in the 26 April 2000 
>working draft of AERT [1].

I agree this is a UA item. Only I think a technique here should be "if you 
specify colors or use a background image specify all colors including 
bgcolor, link, alink, vlink, text and table colors if you are using tables".

Regards Peter Verhoeven
Internet : http://www.magnifiers.org (The Screen Magnifiers Homepage)
Received on Wednesday, 14 June 2000 03:01:38 GMT

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