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Change SC level for flashing content

From: WCAG 2.0 Comment Form <nobody@w3.org>
Date: Tue, 22 Jan 2008 00:49:09 +0000 (GMT)
To: public-comments-wcag20@w3.org
Message-Id: <20080122004909.7B3916B62D@kent.w3.org>


Name: Roger Hudson
Email: rhudson@usability.com.au
Affiliation: 
Document: W2
Item Number: Success Criterion 2.3.2
Part of Item: 
Comment Type: technical
Summary of Issue: Change SC level for flashing content
Comment (Including rationale for any proposed change):
Guideline 2.3.2, which relates to flashing content that is known to cause seizures, contains two Success Criteria. The first, which is at Level A, requires web pages to have no content that flashes more than three times in one second or the flash is below defined \"general flash and red flash thresholds\". The second criterion, which is at Level AAA, requires web pages not to contain anything that flashes more than three times a second.

When it comes to determining the \"general flash and red flash thresholds\" the amount of screen that the flashing content can occupy is precisely defined in one sense, however there appears to be an assumption that typical viewing involves a display area of 1028 x 768 pixels and a viewing distance of 56-66 cm. The Understanding SC 2.3.1 document does not appear to provide any advice or examples for meeting the needs of users with impaired vision who do not conform to these typical viewing conditions.

For screen magnifier users it is not uncommon for the entire display area to occupy less than 25% of a typical 1028 x 768 screen. Also, the field of view for people with tunnel vision or other vision impairments is often very different to the \"typical\". For these people, the combined area of flashing content that is deemed acceptable under the \"general flash and red flash thresholds\" may well be excessive. 

Given that Guideline 2.3 recognises certain flashing content is a known to cause seizures, I believe WCAG 2.0 should provide greater support for people with impaired vision who might also be at risk of seizures, and give greater guidance to developers in how to minimise this risk.

Proposed Change:
Move SC 2.3.2 Three Flashes up to Level AA.
Received on Tuesday, 22 January 2008 00:49:15 GMT

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