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References and contact (was: RE: guideline 7.1 about screen flickering (fwd))

From: Wendy A Chisholm <wendy@w3.org>
Date: Thu, 26 Jul 2001 14:54:09 -0400
Message-Id: <>
To: Charles McCathieNevile <charles@w3.org>, w3c-wai-gl@w3.org

This is an excellent question. I'm glad we have a concrete example to discuss.

I am also glad to hear about the tools that are available - that you Alan 
and Joel.

The question that we need to resolve for this thread is:
is this image a risk for people with photoepilepsy.

The other issue that has come up is:
People with ADD are at risk of being distracted.

Focusing on the photoepilepsy issue:

I just talked with Robin Rowe of Epilepsy Toronto who said she would take a 
look at the image.  She is also sending me broadcast guidelines developed 
for television.  She also put me in touch with Dr. Harding (one of the 
people Gregg referenced), so we will see if he has further information 
about work done with computers and perhaps specifically with the Web.

Here is a reference to an article by Dr. Harding that says patterns can 
cause seizures as well as some colors:

The last bit has some good FAQs and suggestions for people with 
photoepilepsy on how to set up television and computer areas to minimize risk.

Note: computers can trigger seizures in people with 
photoepilepsy.  Computer screens are a light source and it is variations in 
light that are the trigger.  Even natural light sources, such as the sun 
reflecting off of water, can trigger seizures in people who are 
photosensitive.   Anne - please be careful when making claims.

Everyone: please provide evidence of claims that you make.  We need to be 
thorough and correct.

More when I know it.

At 12:21 PM 7/26/01 , Joel Sanda wrote:
>Netscape 6 (Mozilla 0.9.2) from http://www.mozilla.org has a feature in the
>preferences section that lets the user specify how often images repeat
>themselves. The preferences range from never to per image design to always.
>This worked great on the animation heavy site www.animationfactory.com.
>This does NOT work on flash files, but seems to work very well on animated
>The issue of image cycling is tracked in Bugzilla, and the reasoning behind
>the original post was for folks who are distracted by flashing animated
>gifs. The bug ID is 64831 and can be tracked at this URL:
>If Netscape continues to "refresh" their Netscape 6.x browser with builds
>from mozilla then we should see animated images preference make its way into
>Netscape's version of the 6.0 Netscape browser.
>Joel Sanda
>Product Manager
> > p. 303.873.7400 x3021
> > f.  303.632.1721
>-----Original Message-----
>From: Matt May [mailto:mcmay@bestkungfu.com]
>Sent: Thursday, July 26, 2001 9:51 AM
>To: Adam Victor Reed; Charles McCathieNevile; w3c-wai-gl@w3.org; Anne
>Subject: Re: guideline 7.1 about screen flickering (fwd)
>----- Original Message -----
>From: "Anne Pemberton" <apembert@erols.com>
> > If
> > animation on the screen is as distracting to mildly ADD folks, then I
> > expect to see a sizeable number of my students who would be unable to use
> > the computers in the lab. [...]
> > If the animation in games and on the web were as distracting to ADD/ADHD
> > kids as you suggest, the idea wouldn't have come up.
>I think your reasoning here is specious. It is an _extremely_ common problem
>among people (including a number without substantial ADD symptoms) to be
>distracted by animation to the extent that they cannot access content. A
>usability test conducted in '96-97 by User Interface Engineering even
>documented people physically blocking flashing/moving portions of the screen
>with their hands in order to attend to their tasks.
>You are using your class of ADD kids (and the content they use) to make a
>blanket assessment of all people with ADD which those of us on list who have
>it are telling you is fallacious.
> >          When I hit the stop button in IE, the animation stopped. The user
> > has control.
>That's not true in Netscape 6. Or with Flash movies, or the blink or marquee
>elements (and I've seen both in the last week in _new_ ad campaigns designed
>to draw attention from the user).
>My opinion on this image is that it probably doesn't present a risk in terms
>of photoepilepsy (though of course I'm no expert), but it would certainly
>distract some people from nearby content. My solution to an image like the
>one cited would be to loop it for no more than 2 or 3 seconds, since it's
>not offering any more content on future iterations of the loop. This is
>actually what sites like Yahoo require to keep banner ads from distracting
>users unnecessarily.

wendy a chisholm
world wide web consortium
web accessibility initiative
seattle, wa usa
Received on Thursday, 26 July 2001 14:42:48 UTC

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