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I'm going to show you the consequences that there can be
for a blind person when they can't access images on a website.
I'm on a geography page where there's an exercise
so I read the page normally
presentation link, dupilcated link, file link, folder link,
document link, glossary link, auto-evaluation link
The voice synthesis is reading me the links at the beginning of the page - I continue
August 1991, Vilnius, Lithuania, Belin, final story, L, ES, S, Paris
I've found a text
which doesn't tell me very much.
It must be the key for an image.
1 - present the document: type, theme, issues
There's a question, which is asking me to present a document that I don't know about.
A sighted person explained to me that there's an image
which could be described very easily with a text
and that the instructions for the exercise are also in the form of an image file
so they should also be put into text
on the website to make it accessible.
So I don't have the document I should be working on
because it's not described in text
or the instructions, which are in an image file and not in text form
and so I can't do the exercise as normal.
Here is an accessible site on which all the images are described
which is good because it's a site
about beach and swimming access for the blind.
So I'll show you what's given
Audiobeach list, enter
Arriving at the beach...
Graphic: the information board, photo 1
The first photo is apparently a sign,
the information board as marked.
Graphic: tactile boundary markers along the beach, photo 2
The second photo, as I understand it, is apparently
the route across the beach with markers to help people get to the sea.
Graphic: giving out towels and going into the sea, photo 3
I think the third photo is of
the place where towels are given out and returned.
Graphic: board at the water's edge, photo 4
and the fourth shows again a sign at the water's edge,
so everything is clear, it's possible to imagine the photos
thanks to the explanations given by the site.
Another exercise, another somewhat problematic situation, I'm reading a page
1 stroke 6
In your opinion, is the global evolution of the balance of trade for the USA
with its principal commercial partners since 1987
in deficit, positive or stable?
I've found a question which asks me to talk about
the balance of trade for the USA.
I have to analyse something that I don't have on the page.
Although it's not said by my voice synthesis
it must be statistics, a graph, a diagram...
something like that, which isn't found by my voice synthesis
so it required effort from a sighted person,
from the website developer, to add a description.
It's obviously a lot longer than is needed for a simple image like before
but if it's not there then we can't access these statistics
and I can't answer the question.
As we've seen with the diagram of the balance of trade for the USA
some images are complex and difficult to describe,
however there are solutions to this problem.
I'll show you…
List of titles… project 1 diagram
Graphic: press enter for a long description
so the voice synthesis tells me "graphic" and tells me to press enter
if I want a long description
which indicates that a new page will open
on which I can find the description of the diagram.
Enter, description of project diagram - Windows Internet Explorer
description of project diagram
Title of part 1, explanation of project diagram
So here it's easy to see that there's an explanation, it's the first title
Title of part 2, diagram 1
The diagram has two lines, one horizontal and one vertical
crossing in the middle
We have a general description of the diagram
if I continue I find the detail:
list of 4 elements
horizontal line has a minus sign to the left and a plus sign to the right
vertical line has a minus sign at the bottom and a plus sign at the top
All the lines and columns are clearly explained
so I can analyse the diagram and can use it later
when I need it, and when I'm finished I just need to close the window.
The information contained in an image is entirely lost
to someone with sight problems.
Means of substitution must be provided
so that the information contained in the image is replaced in the form of text.
The "alt" attribute is usually used.
It allows a short alternative text to be attached to images as well as
to clickable images and to formula buttons.
These descriptions should offer complete and concise information,
they should be about a dozen words.
When the image is more complex and the description needed to understand it
is longer than a dozen words
it's necessary to use the longdesc attribute
which creates a link to a detailed explanation.
This is regularly the case for describing diagrams
and other complex graphics.
However, not all images need to be treated in the same manner.
Some images are strictly decorative.
It's preferable to handle these in the style sheet.
It's necessary, then, to evaluate which images convey useful information
in the context of the site and which are purely decorative.
Typographic images such as bullet points
can be handled by ul and li tags in the HTML code.
Images can be integrated into the CSS using the list-style-image property.
The transparent images used by some webmasters
to create their page layout need to be indicated.
Someone who uses a voice synthesis program
can't just ignore these bits of text, the way we would visually.
Such images should be given a blank alt attribute.
The browser won't read or display the empty tag.
It should be noted that the technique of using spacer images for page design
can be replaced with the use of CSS,
thus making spacer images obsolete.