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From: Marek Prokop
Date: Tue, Aug 19 2003 12:10PM
Subject: sufficient color contrast
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Hi All,

The Techniques For Accessibility Evaluation And Repair Tools,
particularly the Technique 2.2.1

http://www.w3.org/TR/AERT#color-contrast

states that the brightness difference between background and
foreground color should be at least 125 (according to the
formula given in that checkpoint) to ensure sufficient color
contrast. Is this really sufficient difference? 125 is only 49%
of 255 (what is the most possible brightness difference) and I
read somewhere (unfortunately don't remember where) that at
least 80% brightness difference is necessary.

In fact, on my old monitor, even the difference of 154 is not
enough. 80% would equal 204, what seems to be OK.

Regards,

Marek Prokop



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From: John Britsios
Date: Tue, Aug 19 2003 7:12PM
Subject: Re: sufficient color contrast
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If I got your message right, what is if you use the real web safe colors,
which are only 22, see
http://hotwired.lycos.com/webmonkey/00/37/index2a_page5.html ?

John

----- Original Message -----
From: "Marek Prokop" < = EMAIL ADDRESS REMOVED = >
To: < = EMAIL ADDRESS REMOVED = >
Sent: Tuesday, August 19, 2003 8:02 PM
Subject: sufficient color contrast


> Hi All,
>
> The Techniques For Accessibility Evaluation And Repair Tools,
> particularly the Technique 2.2.1
>
> http://www.w3.org/TR/AERT#color-contrast
>
> states that the brightness difference between background and
> foreground color should be at least 125 (according to the
> formula given in that checkpoint) to ensure sufficient color
> contrast. Is this really sufficient difference? 125 is only 49%
> of 255 (what is the most possible brightness difference) and I
> read somewhere (unfortunately don't remember where) that at
> least 80% brightness difference is necessary.
>
> In fact, on my old monitor, even the difference of 154 is not
> enough. 80% would equal 204, what seems to be OK.
>
> Regards,
>
> Marek Prokop
>
>
>
> ----
> To subscribe, unsubscribe, suspend, or view list archives,
> visit http://www.webaim.org/discussion/
>


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