WebAIM - Web Accessibility In Mind

E-mail List Archives

RE: Is "this-or-that logo" adequate in an ALT text?

for

From: Jukka Korpela
Date: Aug 21, 2002 12:29AM

Jim Thatcher wrote:

> It is not the visual alphabetical sorting that is the
> problem. It is the first letter navigation of the list
> that we all can use, whether with a
> screen reader or not. If the alt text [Home Page] appears,
> "H" will not hit that link. Same for "Link to Home Page."

Point taken. (Besides, the alphabetic sorting is relevant too, especially
when a list of links is presented in speech. Upon arriving at a page, a user
who hears the browser say "42 links on the page" might wish to listen to
them quickly to get a rough idea, then decide what to do next. And
alphabetic order might be an option, and a convenient one. On the other
hand, sorting algorithms _could_ be coded to ignore a leading "[", or even
leading "Link to".)

But the cases where I would (primarily) recommend the use of brackets around
the alt text are not things like "Home page" but what I call content-rich
images, or images that _really_ say more than a thousand words. For example,
an image could contain a pie chart and the alt text would say
"[Pie chart of our sales in 2002]"
or something like that. The alt text is not a _replacement_ for the image;
it does not communicate in words what the image communicates graphically.
Hence, it could be useful to distinguish it from genuine alt texts like
"Our sales in 2002 were dominantly (65 %) Widgets and just 35 % Gadgets"

(In fact, in the pragmatic side, there are three types of alt texts: alt
text that just describes the image; alt text that communicates verbally the
same thing as the image; and alt text that _partially_ communicates the same
thing as the image, hopefully the most important information. For example,
it might not be useful for a pie chart alt text to present _all_ the
information, down to the items with fractions of percentage.)

Images that say more than a thousand words would seldom be links, except in
contexts like a photo gallery where they are thumbnails (and then it might
actually be useful to sort their alt texts as different from normal links on
the page). If there would be some need to make the pie chart image a link,
it's probably better to use a separate textual link instead.

--
Jukka Korpela
TIEKE Tietoyhteiskunnan kehitt