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Re: Check that all information conveyed with color is also available without color

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 17 Jun 2002 05:30:30 -0400 (EDT)
To: Alan Chuter <achuter@teleservicios.com>
cc: <w3c-wai-ig@w3.org>
Message-ID: <Pine.LNX.4.30.0206170525090.13725-100000@tux.w3.org>

To test this particular checkpoint I use lynx to view the content - since it
doesn't support colours or images it gives me a pretty good idea of several
things at once. To check whether images themselves rely on colour to convey
information I just look at them, or I drop my screen colours and contrast to
almost nothing. (I used to use CloseView - the magnification utility that was
always built into the Macintosh which could make everything black on white,
but unfortunately in their wisdom Apple haven't yet seen the need to provide
it in OS X).

Having to test this screen by screen through an image editor seems
frustrating, but does work well.

cheers

Chaals

On Mon, 17 Jun 2002, Alan Chuter wrote:


  This is so obvious that I can't think that nobody has thought of it before.
  The
  WCAG techniques suggest:

    "To test whether color contrast is sufficient to be read by people with
  color
    deficiencies or by those with low resolution monitors, print pages on a
  black
    and white printer (with backgrounds and colors appearing in grayscale)."

  As many people have pointed out printing is not sufficient as the browser
  compensates
  for color problems. Using a B&W monitor it's awkward to compare between
  monitors.

  A simple solution is as follows. My example uses Windows and Microsoft
  Office Photo
  Editor but it will work with other platforms and editors I think.

  1. Use Ctrl+Alt+PrintScreen to copy the image of the browser window
     to the clipboard.

  2. In Photo Editor, select Edit/Paste as new Image

  3. Select File/Properties/Image/Type and switch to grayscale

  4. Repeat step 2

  You now have two copies of the window, one with color and one in grayscale,
  and you
  can toggle between them with Ctrl+F6 to compare.

  Alan Chuter
  achuter@teleservicios.com
  Fundosa Teleservicios (ONCE Foundation), Madrid, Spain
  ONCE (Spanish National Organization of the Blind)



-- 
Charles McCathieNevile    http://www.w3.org/People/Charles  phone: +61 409 134 136
W3C Web Accessibility Initiative     http://www.w3.org/WAI  fax: +33 4 92 38 78 22
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Received on Monday, 17 June 2002 05:30:41 GMT

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