W3C home > Mailing lists > Public > w3c-wai-gl@w3.org > October to December 1998

Re: Alternate text for images.

From: Alan J. Flavell <flavell@a5.ph.gla.ac.uk>
Date: Tue, 22 Dec 1998 22:30:09 +0000 (GMT)
To: "Robert A. Rosenberg" <bob.rosenberg@digitscorp.com>
cc: Andrew McCutcheon <a_mccutcheon@hotmail.com>, w3c-wai-gl@w3.org
Message-ID: <Pine.OSF.4.05.9812222159080.7960-100000@a5.ph.gla.ac.uk>

Quoting an earlier mail that I don't seem to have seen,

On Tue, 22 Dec 1998, Robert A. Rosenberg wrote:

> At 10:47 AM 12/22/98 -0500, Andrew McCutcheon wrote:
> >    Why is it necessary to provide alternate text for all images? 

Well, trivially "because the HTML specification requires it";  more
indirectly because there were good reasons for the HTML specification
to require it. But in particular situations, it may well be reasonable
for the provided text to be empty.  And this seems to be such a case.

So, why would the specification require it?  Some thoughts...

At least the presence of an ALT attribute may be some indication that
the author has given the matter appropriate consideration.  Text-mode
browsers, by default, in the absence of an ALT attribute will
typically display an indication such as [IMAGE], [INLINE], or
[LINK] according to circumstances.  This calls the reader's attention
to the fact that the author had no sympathy for text-mode browsers!

...
> >  Having 'thin blue line' read to me every time I visit
> >a page doesn't mean much to me, it just takes up time. 

Right.

The HTML4.0 spec, in an appropriate place, says:

 "Several non-textual elements (IMG, AREA, APPLET, and INPUT) require
 authors to specify alternate text to serve as content when the
 element cannot be rendered normally."

Note that term: "alternative text to serve as content".

This does not, in general, mean a visual description of the graphic.

Rather, the appropriate thing to do is to provide text that stands as
an alternative way of providing the _functionality_ for which the
image is there.  There are other parts of HTML syntax where the image
can be described, if a description is appropriate: a brief description
in the TITLE attribute, and the LONGDESC pointer to an extended
description.

> If the thin blue line is not a selection (link) or display spot, the alt
> can be ALT=''.

Fully agree.

> If that banner is a link or supplies info (such as
> identifying the page name or contents), then there should be some text in
> the ALT associated with the Banner Image. 

Yes, but having the ALT text be "thin blue line" is probably not
what's wanted in this context.  If the author wanted to provide a
figurative description of the Police Force as the "Thin Blue Line",
they would have put that into their text already!

If the image serves as a link, then its ALT text should be composed
just along the same principles that you'd use in composing any normal
link text: concentrate on the function of the link, not on the
appearance of the image. If there's already some appropriate text
within the scope of the same link, then the appropriate ALT attribute
might still be an empty one.

I hope this doesn't sound too dogmatic.  I realise that some other
commentators consider that a web page is an inherently visual
experience, and that their job is to describe it in every detail to
the reader.  I take the other view (and it seems to be consistent with
the issue that provoked this thread), that a web page possesses
content, and that the author's job is to get that content to the
reader, in whatever way is consistent with the facilities at the
reader's disposal.  The page "morphs" to fit the browsing situation,
so as to get its content over optimally to the reader.  Of course, if
the web page is a picture gallery, then the pictures _are_ its
content, so the result would be much the same by either set of
principles.

                           http://ppewww.ph.gla.ac.uk/~flavell/alt/

all the best
Received on Tuesday, 22 December 1998 17:30:18 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:46:58 GMT