- 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>
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