Title: Accessibility
1Accessibility
2What is accessibility?
- "The power of the Web is in its universality.
Access by everyone regardless of disability is an
essential aspect." -- Tim Berners-Lee, W3C
Director and inventor of the World Wide Web - For a multimedia application to be accessible,
its content must be available to everyone,
including people with disabilities. - Type accessibility in a web browseryou will see
the results you get..
3What is Accessibility?
- Smooth transformation information and services
should be accessible despite physical, sensory or
cognitive user disabilities, work constraints or
technological barriers - Understandable and navigable content content
should be presented in a clear and simple manner,
and should provide understandable mechanisms to
navigate within and between pages. - Content
- can be perceived
- can be navigated
- can be utilised (with keyboard or devices other
than mice) - can be easily understood (even in attention-poor
situations)
4The Human Factor
- 10 to 20 of the population in most countries
have a disability - Not all of those disabilities affect access to
the Web - Vision, hearing, mobility and cognitive problems
do affect access - Average age of population in many countries is
increasing - Vision hearing degrades, changes in dexterity
memory - Some of us become temporarily disabled due to
accident or illness
5Web Accessibility Initiative
- Set By W3
- Sets guidelines for general web accessibility but
also applies to accessibility in general - How do we make things accessible?
- Where can we look for more information on
accessibility? - Full page - http//www.w3.org/WAI/
- Quick Tips - http//www.w3.org/WAI/References/Quic
kTips/ - Full checklist - http//www.w3.org/TR/WCAG10/full-
checklist.html and http//www.w3.org/WAI/gettingst
arted/ - How they view the web - http//www.w3.org/WAI/EO/D
rafts/PWD-Use-Web/
6Why do it?
- A proportion of your audience is disabled
- That should be enough reason why.
- UK
- http//news.zdnet.co.uk/story/0,,t269-s2105208,00.
html - http//www2.warwick.ac.uk/fac/soc/law/elj/jilt/200
0_1/chung/ - http//www.drc-gb.org/
- America Section 508
- http//www.section508.gov
7BUT
- Nine in ten of the UK's top companies are failing
to make their Web sites accessible to people with
disabilities. - http//www.theregister.co.uk/2004/01/20/disabled_u
sers_struggle_to_access/ - http//www.webcredible.co.uk/user-friendly-resourc
es/web-accessibility/
8Accessibility Means Dull
- WRONG!!!!!!
- An accessible application is NOT dull, plain
boring text - WAI guidelines tell you how to do things
accessibly, they dont say Dont do it - Accessibility is not about restricting your
multimedia/graphical design it's about enhancing
it!
9Quick Tips
- Images animations Use the alt attribute to
describe the function of each visual. - Multimedia. Provide captioning and transcripts of
audio, and descriptions of video. - Hypertext links. Use text that makes sense when
read out of context. For example, avoid "click
here." - Page organization. Use headings, lists, and
consistent structure. - Graphs charts. Summarise
- Allow the user to personalise
10Disability Guidelines
11Visual impairments
- Three main groups
- Blind
- Low vision (poor visual acuity, tunnel vision,
etc.) - Colour blind (_at_ 10 of male population)
- Red/green
- Blue/yellow
- No colour perception
12Technologies Used
- Screen readers (JAWS, WindowEyes, Home Page
Reader) - Braille readers
- Text browsers directing content to speech
synthesizers - Screen magnifiers (ZoomText and others)
- Large monitors, low resolution (lt 640x480)
- Personalise (font sizes colour combinations)
13Assistive technologies
- Braille readershttp//www.humanware.com/
- JAWShttp//www.freedomscientific.com/
- Home Page Readerhttp//www.spectronicsinoz.com/pr
oduct.asp?product3997 - Zoomtexthttp//www.aisquared.com/index.cfm
14Problems for blind people
- Complex images (e.g. graphs or charts) that are
not adequately described - Video that is not described in text or audio
- Tables that do not make sense when read serially
(in a cell-by-cell or "linearised" mode) - Document formats that may be difficult for screen
readers to interpret
15Text
- Provide a text equivalent for every non-text
element This includes images, graphical
representations of text (including symbols),
image map regions, animations (e.g., animated
GIFs), applets and programmatic objects, ascii
art, frames, scripts, images used as list
bullets, spacers, graphical buttons, sounds
(played with or without user interaction),
stand-alone audio files, audio tracks of video,
and video
16Does the text help the blind user?
The text is not an equivalent of the graphical
information An equivalent might be Map showing
the location of Monash campuses together with a
long description indicating distance from and
relative location to the city
17Examples of text equivalents
Look at your page in a text browser to get an
idea of how to write text equivalents
18Barriers for people with low vision
- Absolute font sizes that do not change (enlarge
or reduce) easily - Inconsistent layouts, are difficult to navigate
when enlarged due to loss of surrounding context - Poor contrast, and contrast that cannot be easily
changed through user override - Also some of the barriers listed for blindness
19Colour Blindness
20Colour Blindness
21Barriers for people with colour blindness
- Meaning that is conveyed by colour alone
- Colour that is used as a unique marker to
emphasise text - Text that inadequately contrasts with background
colour or patterns - Solution - Ensure that all information conveyed
with colour is also available without colour, for
example from context or markup
22Examples of use of colour alone
23Which is more accessible to blind or visually
impaired people?
24Hearing Impairments
- Deafness
- Deaf community is a linguistic community
- First language is sign language
- Hard of hearing
25Barriers for people with hearing impairments
- Use of long sentences, uncommon or sophisticated
vocabulary - Lack of captions or transcripts of audio
- Lack of content-related images in pages full of
text, which can slow comprehension for people
whose first language may be a sign language
instead of a written/spoken language
26Seizures
- Seizure disorders
- Triggered by visual flickering or audio signals
at a certain frequency - People with seizure disorders may need to turn
off animations, blinking text, or certain
frequencies of audio
27Photosensitive Epilepsy
- allow users to control flickering, avoid causing
the screen to flicker - allow users to control blinking, avoid causing
content to blink - allow users to freeze moving content, avoid
movement in pages - People with photosensitive epilepsy can have
seizures triggered by flickering or flashing in
the 4 to 59 flashes per second (Hertz) range with
a peak sensitivity at 20 flashes per second as
well as quick changes from dark to light (like
strobe lights). - http//www.epilepsy.org.uk/info/photo_web.html
28Other Considerations
- Cognitive impairments
- Dyslexia
- Dyscalculia
- Difficulty processing written or spoken language,
or numbers when read visually or heard - May rely on getting information in several ways
at the same time (e.g. pictures / animation and
text) - Provide alt text that can be converted to audio
to supplement visuals - Dont use unnecessarily complex language
- Complex sentence structures
- Use of long words or sophisticated language
29Quasi-Disabilities
- These conditions create similar experience
- Low spec PCs
- Missing Plug-ins
- No Speakers
- Small Display
- Eyes Busy/Hands Busy
- Noisy Environment
30Macromedia And Accessibility
- http//www.adobe.com/accessibility/
- Director - http//www.adobe.com/macromedia/accessi
bility/features/director/
31Tools
- Aprompt - http//aprompt.snow.utoronto.ca/
- Betsie - http//www.bbc.co.uk/education/betsie/
- Vischeck - http//www.vischeck.com/
- Free accessibility Test - http//www.usablenet.com
/ - WAVE - http//wave.webaim.org/index.jsp
- Lynx Viewer
- http//www.delorie.com/web/lynxview.html
- Might be useful for HCI section of projects
32Other stuff
- http//www.rnib.org.uk/xpedio/groups/public/docume
nts/code/public_rnib008789.hcsp - http//www.w3.org/WAI/wcag-curric/
- http//ncam.wgbh.org/webaccess/magpie/
- Beyond ALT Tag - http//webpac.staffs.ac.uk8080/i
nternal/beyond_alt_text.pdf - Accessibility Design - http//webpac.staffs.ac.uk
8080/internal/accessibility_methodology.pdf - http//www.nomensa.com/resources/articles/
- http//www.usabilitynews.com/news/article1321.asp
- http//www.usabilitynews.com/news/article1274.asp
- http//www.mardiros.net/accessible-web-design.html
- http//directory.google.com/Top/Computers/Software
/Internet/Clients/WWW/Browsers/Accessibility/ - http//www.webaim.org/
- http//www-3.ibm.com/able/guidelines/web/accessweb
.html - http//trace.wisc.edu/world/web/
- http//www.nfb.org/tech/webacc.htm
- http//library.uwsp.edu/aschmetz/Accessible/websur
veys_p.htm - http//hotwired.lycos.com/webmonkey/99/20/index0a.
html?twdesign