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Re: Suggested issues that may be addressed in next version of guidelines

From: Charles McCathieNevile <charles@w3.org>
Date: Sat, 7 Aug 1999 18:46:48 -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.4.10.9908071837430.16228-100000@tux.w3.org>
I agree with Jason that in many cases it is impossible to create a
non-textual version of a text and still communicate the same ideas. In many
more cases it is prohibitively expensive (think of the difference in price
between writing a book and producing a movie). However there are many cases
where it is possible - a classic example is the use of graphs and charts or
modern algebraic representation to illustrate mathematical concepts that are
extraordinarily difficult to express in language (although I know that Jason
and others have managed to perform mathematics through language - difficult
and impossible are very different).

The notion of equivalence which we use allows and requires us to understand
that some equivalents are better replacements than others. This applies to
both textual and non-text equivalents. Perhaps we need to make the point more
clearly in our definitions.

Charles McCN

On Sat, 7 Aug 1999, Jason White wrote:

  The one phrase in Charles' contribution to which I take exception is
  "non-text equivalents". As Gregg has persuasively argued on several
  occasions, it is not feasible to propose the inclusion of "non-text
  equivalents" of textual content, except in cases where the concepts being
  conveyed are sufficiently simple and every-day to permit a clear and
  widely recognisable visual representation. One needs to think, rather, in
  terms of visual supplements that clarify the meaning of textual material,
  for example in the manner that a chart or graph can be used to summarise a
  data table, or in which an image can identify the subject of a newspaper
  article, or in which layout can convey the structure of a document.

and so forth...
Received on Saturday, 7 August 1999 18:47:00 UTC

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