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Re: Images with captions and alt

for

From: Penny Roberts
Date: Aug 11, 2005 12:00PM


On Wed, 10 Aug 2005 14:35:55 +0300 (EEST) "Jukka K. Korpela"
< <EMAIL REMOVED> > wrote:

> On Wed, 10 Aug 2005, Penny Roberts wrote:

> > For example: an image has a caption (which comes straight after the image
> > in the code) reads "Figure 6: The catalogue search results screen" and the
> > alt tag is "Catalogue screen showing search results". Wouldn't that be
> > redundant to anyone reading the screen with images turned off and just
> > plain annoying and time wasting to anyone hearing the screen?
>
> It would be annoying indeed. But does it help the user to hear or see the
> text even once? After all, neither the caption nor the alt text presents
> the information content of the image; they just refer to it.

I think that I didn't make the situation very clear: the fact that it is a
catalogue screen showing search results *is* the information
being conveyed, the actual content of the screen (the search results) is
not important (so it could have "Foo Bar" for every title) .
To put it into context it is part of an interactive tutorial used
by university students to learn how to use the catalogue, by the time they
see the image they will already have run a search for themselves and
should have their own results in front of them. Because different people
learn in different ways we have found that whilst many are content with
text that says "you should now see a screen showing search results" some
need the visual reassurance of an image that confirms that they have
reached the right stage and some require the further assurance of the
caption to say "yes this is the search results screen".

> This is a tough question, and it depends on the nature and purpose of the
> image. For example, sometimes a purely decorative image has a caption
> (as text, not as embedded into the image). It is not quite sufficient to
> use alt="", since the user will see or hear the caption and wonder what it
> is about. In this special case, even alt="(decorative image)" would make
> some sense.

In this case the image is functional and necessary and the user would
hear the caption which describes it, so would a parallel to your example be
to make the alt="[screenshot]"

> An adequate textual replacement for some catalogue screen showing search
> results would consist of text that explains, in sufficient detail as
> required by the purpose of presenting the material, what the search
> results consist of and how they are presented. This could consist of the
> transcript of the same search using a text-only user interface.

The accompanying text already describes how to run the search and what they
will find on the screen (for instance that the closest match to their
search term is in bold text) and at this point they have (hopefully)
already run the search for themselves.
I suppose that a supplementary problem is that anyone using AT to
do the tutorial will also use it to run the search and therefore may not be
seeing the screen in the image anyway!

Penny
<*>
Penny Roberts
Radcliffe Science Library
Oxford