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Background images

From: Loretta Guarino Reid <lguarino@adobe.com>
Date: Thu, 24 Apr 2003 12:45:23 -0700
Message-Id: <200304241945.MAA01863@patagonia>
To: Joe Clark <joeclark@joeclark.org>
cc: WAI-GL <w3c-wai-gl@w3.org>

Joe,
  I've appended the current draft of Checkpoint 1.5. Only when we get to Level 
3 does the checkpoint "ban" text content over background images. At Level 1, 
it is sufficient if your User Agent lets you control the display of the 
background image.
  The largest problem with text over background images isn't that the author 
designed it with poor contrast in the first place (although colorblindness 
considerations can make this more of a challenge). But when a user needs to 
configure the text and background colors, the configured text color may no 
longer provides sufficient contrast with the background image. This checkpoint 
is trying to make it possible for that class of users to read the text.

	Loretta



Checkpoint 1.5 Ensure that foreground content is easily differentiable from 
background for both auditory and visual presentations.

        
Success criteria 

        
You will have successfully met Checkpoint 1.5 at the Minimum Level if: 

	1.text content that is presented over a background image or pattern is 
implemented using mechanisms that allow the user to display the text without 
the background image or pattern.

You will have successfully met Checkpoint 1.5 at Level 2 if: 

	1.when text content is presented over a background image or pattern, the text 
is easily readable when the page is viewed in 256 grayscale.

You will have successfully met Checkpoint 1.5 at Level 3 if: 

	1.text content is not presented over a background image or pattern OR the 
text is easily readable when the page is viewed in black and white (no 
grayscale).
	2.audio content does not contain background sounds OR the background sounds 
are at least 20 db lower than the foreground audio content.
	3.text content is not presented over a background image or color OR the 
colors used for the text and background or background image pass the following 
test (from Techniques For Accessibility Evaluation And Repair Tools, dated 
April 26, 2000):  <<details of the test omitted>>
Received on Thursday, 24 April 2003 15:45:47 GMT

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