[adeel420] Making the Web Accessible for the Blind and Visually Impaired
- From: "Sajid Iqbal" <sajid_cyberspace@xxxxxxxxxx>
- To: <"Undisclosed-Recipient:;"@smtp-1.hotpop.com>
- Date: Mon, 25 Nov 2002 22:33:06 +0500
Making the Web Accessible for the Blind and Visually Impaired
By Mike Paciello (mpaciello@xxxxxxxxxxxxxxx)
This is the first of a series of three articles which will describe many of the
barriers people with disabilities experience as they try to use the World Wide
Web.
Additionally, I will provide potential solutions. The goal of each article is
simple: AWARENESS. If I can succeed in educating webmasters, internet service
providers (ISPs), and web designers regarding the needs of people with
disabilities, then I believe the greatest barrier will have been broken.
Note too that these articles are generally "high-level" descriptions. You can
find the deeper, more technical information at my website:
http://www.webable.com.
This article will focus on the needs of the "print impaired".
Print-impaired persons include the blind and low vision users. However, the
term is not limited to individuals who experience sensory loss in their eyes.
Print-impaired people also include those who have limited or no use of their
hands or fingers in order to turn pages of a book or to access a keyboard or
mouse interface for electronic documents. People with cognitive disabilities
(for example, dyslexia) are sometimes included within the print-impaired
category.
It's important for the sake of information and client design that you keep in
mind the broader category of the print-impaired. By doing so, you're sure to
design user interfaces and information that is accessible to the blind and
visually impaired.
Blind users generally will have either a synthetic speech synthesizer or
refreshable braille display attached to their PC. The speech synthesizer
vocalizes the onscreen data. Refreshable braille displays convert ASCII
character streams to braille and then output that data to a braille display.
(If you've never seen a refreshable braille display, rent the movie "Sneakers".
The movie character "Whistler" is blind. He uses a refreshable braille display
to read the imbedded code on a computer microchip.)
The key to reading a web document or displayed server messages is that the
output stream is ASCII text. Since many blind users rely on character-cell
browsers (LYNX, W3, Cern Line Mode Browser) that read the ASCII in conjunction
with their synthesizers and braille displays, it is critical that imbedded
images also contain meaningful text descriptions. This is accomplished by using
the ALT attribute to the [INLINE] tag in HTML.
If you cannot use the ALT attribute (probably for asthetic reasons), try to
include a description of the image, picture or graphical element somewhere
physically close to the image as possible. This is even more important when the
image intent is to convey a concept. Be sure to use text to convey conceptual
images.
Never use bitmap images of text. They are impossible for the blind to read. Low
vision users can enlarge them, but persons who are legally or totally without
any sight, can never read text images.
Navigation is a challenge for blind and visually impaired users. Whereever
possible, try to minimize the number of multiple hypertext links that appear in
a single line of text.
Navigation is also difficult in web pages that feature multicolumn displays.
These are a nightmare for the blind. In addition to speech synthesizers, blind
users require application software called "screen access" or "screen reader"
software. Most of these applications (including those for GUI interfaces) are
only capable of reading one line of text at a time. Thus, when the browser
displays a multicolumn document, the screen reader reads each line, jumping
from column to column until it reaches the end of the line. This makes it very
difficult for the user to follow, since there is no logical construct for the
screen reader to follow. If you are a publisher of online journals, newspapers,
or magazines, consider providing an alternative view of your text that is not
multicolumn in format and that can be downloaded.
Client (particularly browser) developers should look at opportunities to
include hooks for screen readers and screen magnifiers. Additionally, in every
case, include keyboard equivalents for mouse commands.
Lastly, the richness of the description of the document structure is the
greatest friend of the blind user, particularly those who use braille displays
or print documents that must be translated to braille. As a result, HTML is
ideal because it provides knowledge about a document's construct that is
important to the braille translation software. Titles, paragraphs, lists,
tables, etc..etc.. all contain their own formatting constructs. Braille
translation software identifies the entity, associates that with a format, and
then does the proper translation for the blind user.
Documents that contain no tangible entity or formatting information are useless
to blind users. Recently, this issue was raised to Adobe concerning their
Portable Document Format (PDF), which is becoming increasingly popular on the
Web because of it's appealing visual appearance through a browser. This is
ideal for a sighted user, but the source document provides no internal element
desciptors that can be easily accessed and subsequently translated for the
blind user. The good news is that Adobe is aware of the problem and has
recently responded with an accessibility plan to deal with the inaccesibility
of PDF.
Other related posts:
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