FW: contrast in video



From: Geoff Freed [mailto:geoff_freed@wgbh.org] 
Sent: Thursday, April 22, 2010 1:47 PM
To: jimallan@tsbvi.edu
Cc: Madeleine Rothberg
Subject: Re: contrast in video


hi, jim:

i'm unaware of a formal color/contrast settings specifically for video
accessibility (analogous to the ratios set for web pages and images). i'm
adding madeleine, however, because she may know something.  madeleine?

giving the user a wide latitude of adjustment would certainly be useful but
setting a strict level might be hard since video is, by nature, a moving
target and so color and contrast are always changing.  while it's true
computers and monitors allow users to set contrast and brightness levels,
some OS settings for contrast affect video as well:  for example, when you
change contrast settings on the mac using the accessibility panel, it
affects video as well.  this is *not* the case on windows, however (at least
not on XP).


On 4/22/10 12:57 PM, "Jim Allan" <jimallan@tsbvi.edu> wrote:

UAAG20 has a success criteria
4.9.11 Adjust Playback Contrast and Brightness.  User has ability to control
the contrast and brightness of the content within the playback viewport.

Most standalone player have a contrast control. We were wondering if you
knew of any contrast requirements for accessibility of video?
I know WCAG has them for text. I doubt they will apply to video.
Some folks with vision problems have contrast issues. Television and
monitors allow contrast and brightness adjustment so users can adjust their
monitor to meet their viewing preferences. Perhaps, we need something like
adjustment to 50% higher or 50% lower than what is delivered in 1%


Jim Allan, Accessibility Coordinator & Webmaster
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
"We shape our tools and thereafter our tools shape us." McLuhan, 1964

Received on Thursday, 22 April 2010 19:16:22 UTC