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Re: guideline 7.1 about screen flickering

From: Andrew Kirkpatrick <andrew_kirkpatrick@wgbh.org>
Date: Thu, 26 Jul 2001 16:23:50 -0400
To: Terrie King <tking@ucp.org>, <w3c-wai-ig@w3.org>
Message-ID: <B785F496.4B6E%andrew_kirkpatrick@wgbh.org>
Curious to see what these would look like, I made a demo that uses these
images.  You can see flickering images (in macromedia Flash) at 4, 7, 20,
and 59 Hz at http://ncam.wgbh.org/richmedia/flicker_demo_start.html.  The
effect of all four together is awful, so I put a link next to each to see it
by itself.  That only makes it worse.  Having made these and looked at them
quite a bit today, I wholeheartedly support the WCAG and 508 screen flicker

I assume that these qualify as a violation of the rules...or does the whole
screen need to flicker?



On 7/24/01 10:44 AM,  Terrie King (tking@ucp.org) wrote:

> Okay, experts!  I have been asked to put another agency's animated gif on my
> Web site.  I am hesitant to  use it because of guideline 7.1--"Until user
> agents allow users to control flickering, avoid causing the screen to
> flicker."  Here's the link to the checklist item:
> http://www.w3.org/TR/WCAG10/wai-pageauth.html#tech-avoid-flicker
> How can I determine if the gif in question is within the guidelines?  (gif
> attached)  If it is not, I guess I can ask for a non-animated gif.
> Terrie
> ---------------------------------------------
> Terrie L. King
> Internet Marketing Manager
> UCP National
> 1660 L Street, NW, Suite 700
> Washington, DC  20036
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Andrew Kirkpatrick, Technical Project Coordinator
CPB/WGBH National Center for Accessible Media
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Received on Thursday, 26 July 2001 16:24:25 UTC

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