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Some concrete suggestions Re: Cognitive issues (was Re: woodcutter)

From: Charles McCathieNevile <charles@w3.org>
Date: Mon, 3 Apr 2000 05:13:10 -0400 (EDT)
To: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
cc: Web Content Accessibility Guidelines <w3c-wai-gl@w3.org>
Message-ID: <Pine.LNX.4.20.0004030444280.9239-100000@tux.w3.org>
These are just-poured with very wet concrete, so can be changed quite a lot
before it cures.

Illustrate text content with appropriate graphics or multimedia.

Some things can clearly be illustrated to make them more accessible. Examples
abound in textbooks (quantum physics, electrochemistry, architecture,
construction of all kinds, road rules and navigation techniques) Flow charts
and structure diagrams can be used to illustrate complex ideas and

For people who have difficulty reading, this sort of illustration can greatly
improve their understanding of or ability to use Web content. For people who
are unable to read without extreme difficulty, this can make the difference
between having an idea what something is about and using whatever techniques
are available to understand the content (including reading software, finding
related material through metadata-based retrieval, or further study of the
available content), or not being able to understand what sort of concepts are
being presented.

Some techniques:

  Use sound. 
    Although this will not work for everyone (any more than a longdesc is
    helpful to anyone) there are some kinds of content that can be easily
    illustrated with sound. The emergence of markup languages for voices
    and music will make it easier to do this in an accessible manner.

  Use clearly drawn graphics with good contrast. 

  Use internationally or widely recognised symbols, with appropriate colours
    There are many symbols which are widely recognised when used in an
    appropriate context. Traffic symbols, those used in airports and hotels,
    and more specialised symbols such as those in flowcharts and circuit
    diagrams can all help clarify meaning for an audience that understands
    the content matter but has difficulty with the text.

  Use photographic images for specific references, drawings or symbols for
  general references
    Where a piece of content is about a specific person, it is appropriate to
    use an image of that person. Where a piece of content is about cars in
    general it may be more appropriate to use a stylised or generic drawing
    of a car

  Use layouts that reflect the structure of the content
    One of the reasons for including structure is so that it can be
    represented in many media. Most visual readers are used to deriving
    semantics from presentation conventions that are not fixed, but are
    nonetheless describable - things that are larger or decorated are likely
    to be headings, layout that has a hanging indent (where this is not the
    norm) or bullets or numbers is likely to be some kind of list, and what
    is indented is likely to be especially or only relevant to the initial
    line or items in it, etc.

  When user agents or appropriate language provide the ability to control
  animation, use it to demonstrate complex motions

My knowledge of graphic communication is limited - I am sure we can find
better and refine this. Likewise with sound and animation. 

Charles McCN

Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
Location: I-cubed, 110 Victoria Street, Carlton VIC 3053
Postal: GPO Box 2476V, Melbourne 3001,  Australia 
Received on Monday, 3 April 2000 05:13:14 UTC

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