W3C home > Mailing lists > Public > w3c-wai-ig@w3.org > January to March 2005

RE: Screen Flicker Test

From: Bailey, Bruce <Bruce.Bailey@ed.gov>
Date: Tue, 1 Mar 2005 15:54:12 -0500
Message-ID: <CCDBDCBFA650F74AA88830D4BACDBAB50712FEB8@wdcrobe2m02.ed.gov>
To: "Lubow Scott" <lubow_scott@bah.com>
Cc: <w3c-wai-ig@w3.org>
My personal experience it that one doesn't need to know the exact flickering rate, just that something is flickering.  If an animation or whatever is cycling at twice per second or slower, well you can count that.  If the item in part or in whole is noticeably strobing at all, but faster than you could humanly hope to to measure with a stop watch, well then it is plainly in the danger zone!
 
You might wonder if the strobing is at speed enough to be 55 hertz or faster.  Well, unless you have the super-human ability to routinely notice the static frames being refreshed on your television (or computer monitor), the answer would be no.  An object that alternates in color between black and white at 55 hertz doesn't appear to strobe, it just looks white.  Well maintained fluorescent lights work this way. 

-----Original Message-----
From: w3c-wai-ig-request@w3.org [mailto:w3c-wai-ig-request@w3.org] On Behalf Of Lubow Scott
Sent: Tuesday, March 01, 2005 1:26 PM
To: w3c-wai-ig@w3.org
Subject: Screen Flicker Test


Hi All,
Please forgive me if this question has been asked numerous times.  Does anyone know a way to test an object to determine if it flickers between 2 and 55 Hz?  I saw somewhere that you could use a stop watch but I can't imagine someone being able to count 55 times in a second.  
Thanks in advance,
Scott
 
Received on Tuesday, 1 March 2005 20:54:44 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 19 July 2011 18:14:19 GMT