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Re: guideline 7.1 about screen flickering

From: Terrie King <tking@ucp.org>
Date: Wed, 25 Jul 2001 17:46:53 -0400
Message-ID: <030901c11553$51a7b9e0$7502000a@ucp.org>
To: "David Woolley" <david@djwhome.demon.co.uk>, <w3c-wai-ig@w3.org>
Thanks for your insight, Dave.  By the way, how does one technically
determine the hertz rate?

Terrie

----- Original Message -----
From: "David Woolley" <david@djwhome.demon.co.uk>
To: <w3c-wai-ig@w3.org>
Sent: Wednesday, July 25, 2001 2:52 AM
Subject: Re: guideline 7.1 about screen flickering


> Charles wrote:
> >
> > I am not so sure. The thing moves in my viewer at the sort of rate that
is
> > potentially a problem (between 5 and 50 hertz, roughly) for people with
>
> The frame rate is 1/80ms, and there are four circuits in 30 frames,
> so the complete sequence repeats at about 1.666 Hz, so I suspect it
> may be too slow.
>
> > photosensitive epilepsy, and is distracting for people with
concentration
> > difficulties. I think if it is going to be fine it will be so on the
basis
>
> However it is extremely distracting in the peripheral vision, so it
> would fail on that point.
>
> Incidentally, it's not technically accurate, as a real primary radar would
> have a fast leading edge and a slow exponential trailing edge, whereas
> this picture has slow leading and trailing edges.
>
Received on Wednesday, 25 July 2001 17:43:37 GMT

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