- From: Christophe Strobbe <christophe.strobbe@esat.kuleuven.be>
- Date: Wed, 12 Sep 2007 11:57:11 +0200
- To: wcag <w3c-wai-gl@w3.org>
Hi, The following question came out of some work on the Unified Web Evaluation Methodology (UWEM) [1]. The May 2007 draft of WCAG 2.0 defines blink as "turn on and off between 0.5 and 3 times per second", with a note saying: "The slower blink is in contrast with flashing, which refers to rapid changes in brightness which can cause seizures. See general flash and red flash thresholds." However, the definition of blink does not specify a contrast ratio between the on and of states, so any blinking fails the success criterion, even if the contrast between the two states is very low. Of course, low contrast would fail SC 1.4.3 (Contrast (Minimum)), but evaluators, especially automated tools, would want to establish whether blinking content fails SC 2.2.2 by itself, regardless whether it passes or fails SC 1.4.3. So, my question is: does *all* blinking content fail SC 2.2.2? (I assume it currently does.) Should we add a note about this to the definition of blink? Best regards, Christophe [1] <http://www.wabcluster.org/uwem1_1/> UWEM is based on WCAG 1.0; checkpoint 7.2 covers blinking content. -- Christophe Strobbe K.U.Leuven - Dept. of Electrical Engineering - SCD Research Group on Document Architectures Kasteelpark Arenberg 10 bus 2442 B-3001 Leuven-Heverlee BELGIUM tel: +32 16 32 85 51 http://www.docarch.be/ Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
Received on Wednesday, 12 September 2007 09:57:22 UTC