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4.4.1 and 4.4.2

From: Simon Harper <simon.harper@manchester.ac.uk>
Date: Thu, 3 Dec 2009 09:39:44 +0000
Message-Id: <050B0B31-515D-4569-ACA9-0E4BDAEFFA1D@manchester.ac.uk>
To: UAWG list <w3c-wai-ua@w3.org>
Again, Kim and I had this action, but looking at this I think we  
should amalgamate these two into:

4.4.1 The user interface never violates the general flash or red  
flash thresholds, or flashes more than three times in any one second  
period (Level A)

Intent of Success Criterion 4.4.1:
The intent of this Success Criterion is to guard against inducing  
seizures due to photosensitivity, which can occur when there is  
general flashing, or red flash. A potentially harmful flash occurs  
when there is a pair of significantly opposing changes in luminance,  
or irrespective of luminance, a transition to or from a saturated red  
occurs.

Examples of Success Criterion 4.4.1:
A single, double, or triple flash -- as long as it does not include  
changes to or from a saturated red -- may be used to attract a user's  
attention, or as part of an interface animation.

Related Resources for Success Criterion 4.4.1:
ITC Guidance Note for Licensees on Flashing Images and Regular  
Patterns in Television: http://www.ofcom.org.uk/tv/ifi/guidance/ 
legacy/vrs_code_notes/flsh_imgs/gn_flash.pdf


Best
Kim and Si.
Received on Thursday, 3 December 2009 09:40:11 UTC

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