W3C home > Mailing lists > Public > w3c-wai-ig@w3.org > January to March 1998

WD-WAI-PAGEAUTH-0203 and the use of ALT text

From: Alan J. Flavell <flavell@a5.ph.gla.ac.uk>
Date: Thu, 5 Feb 1998 20:41:57 +0000 (GMT)
To: w3c-wai-ig@w3.org
Message-ID: <Pine.OSF.3.96.980205192149.10146C-100000@a5.ph.gla.ac.uk>

Greetings.  I refer to the draft guidelines as above.

(Excuse me but I am not subscribed to your list; an email copy of any
responses would be appreciated, although I would see them anyway in due
course in your archives). 

You were kind enough to include mention of my www article on the topic of
ALT texts. I have to say frankly that this article originally approached
the subject from the point of view of accessibility to text mode browsers,
and not specifically to persons with disabilities, an area in which I have
no particular expertise; it has become clear that some of the details in
my article were inappropriate for the latter purpose, and I have reworked
them over time to try to reach a good compromise.

However, there remain some points on which I would take issue with
the guidelines as presented.

The principle from which I have proceeded is that the ALT text is
literally "alternative text", i.e it provides a textual substitute for the
_information_ or _purpose_ of the image.  There are other attributes
(TITLE and, now, LONGDESC) available for other purposes such as
_describing_ the image. 

At:

"Provide alternative text for all images and image maps."

it says:

"Each image should have alternative text that describes the function of
the graphic"

I disagree.  What is wanted is not a _description_ of the function, but
the function itself.  Of the examples given, "Section Title: Banana
Products,"  and "Search Button." seem fine, but "Graph of population
versus age," is _no_ alternative text presentation of the _information_. 
Rather, this would be more appropriate IMO as the TITLE attribute.  What
the text mode reader needs to know is not _that_ there is a graph present,
but what the heck does the graph show that is relevant to the topic under
discussion?  If the text already makes that clear, then maybe ALT="" is
appropriate.  Surely, calling the text-mode reader's attention to a graph
that they can't read, while telling them nothing about what information it
contains, is worse than useless?  

And in the "possible strategies", again we have a description of
information, instead of the information itself.  <IMG src="logo.gif" 
alt="XYZ Logo"> cannot possibly be right, in my view.  If the logo is
there in order to identify the company, then the name of the company would
be appropriate, e.g ALT="XYZ Corp", whereas if the company name is already
present in clear text, then ALT="" would seem more appropriate, unless
their logo is somehow pertinent to the topic under discussion, rather
than mere identification.

I reiterate: surely stating that a logo is there is unproductive if the
only purpose was to identify the company, and equally unproductive if the
purpose was to acquaint the reader with this company's logo.  In no sense
is ALT="XYZ logo" an alternative text that can substitute for the purpose
of the image, unless the image's purpose was to introduce the logo into
the discussion for some reason. 

With a little thought it's possible to choose ALT texts such that the text
reads naturally, and the text-mode reader is scarcely aware of the
"seams". Pages that have been composed "by rote", putting ALT="XYZ logo" 
whenever the logo occurs, tend to read idiotically on a text mode
browser.  Almost as bad as those that have ALT="large red bullet" etc.

I note the advice given at "Provide descriptive titles for all images used
as links." and the example 

        <A href="home.html" title="XYZ company home page">
        <IMG src="logo.gif" alt="XYZ logo">
        </A>

I'm thinking this one over.  I had always been accustomed to marking
this up something like

        <A href="home.html">
        <IMG src="logo.gif" alt="[XYZ company home page]">
        </A>

but I can see the point - though again I have the same reservations about
using ALT to _describe_ the information, rather than to substitute for it. 

"Avoid ASCII art. Replace it with an image and alternative text."  That
guideline is addressing the main body of the text, but it is clearly also
applicable to ALT texts.  There is as yet no reliable way of providing a
decorative HR (along the lines of the old HTML3.0 <HR SRC="...">
proposal).  Well-implemented style sheet support should make something
possible, but meantime, page designers are going to continue using IMGs in
place of HRs, and it's hard to know what to use as the ALT text. 
Previously I had been suggesting the use of "ASCII art", but here I have
taken your recommendation on board, and categorised the use of "ASCII art" 
in an ALT text as deprecated by accessibility guidelines.   You do have
a nice suggestion that will be appropriate in a proportion of
cases, I see.

Turning to the "Central" document, in 13.3 the same 'ALT="XYZ logo"'
example appears.  So often when I feel an ALT has been poorly chosen, it
is because it is _describing_the_image_ when it ought to have been
_substituting for the purpose of the image_.  Referring to the " tips and
tricks concerning alternative text ", I read: 

"2.Sometimes it is easier to describe what the function of the graphic is
rather than what it is or looks like. "

It's not only "sometimes easier": I would say it is often more
appropriate.  I would rather say "The ALT text should substitute for the
_purpose_ of the image; the mere description of the graphic will rarely be
appropriate for doing that". 

I hope these comments are useful.  Sorry if they were a bit long winded.

best regards
Received on Thursday, 5 February 1998 15:42:21 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 19 July 2011 18:13:38 GMT