Transcript Usability_05_Accessibility

Fundamentals of Graphic
Communication
3.5 Accessible Design
Overview
•
•
•
•
•
What is accessibility?
Why is it important?
Design guidelines
Types of disabilities
Accessibility testing
What is accessibility?
• Accessibility is the degree to which technology is
usable by people with disabilities
• Universal access is the philosophy of designing
technology and information to be usable by all
people without specialized adaptations
Accessible technology
• Assistive hardware
– Allow disabled users to interact with the computer
– Examples
• Specialized keyboards
• Head trackers
• Braille terminals
Matias Corporation
Accessible technology
• Accessibility software
– Designed to provide an accessible interface between
other software and the user
– Examples
• Voice recognition
• Speech synthesis
• Screen readers
• Mouse / keyboard helpers
• We want software to be accessible; that is, to
work transparently with accessible technology
without sacrificing quality
Why’s it important?
• There are millions of disabled people in the US
– Non-accessible products limit your audience
• It’s the law
– Section 508 requires government-funded websites to
meet accessibility guidelines
• It’s a nice thing to do
– Share your creations with the world
• Accessible design often results in good design
– Easy-to-use products benefit everyone
Good Grips
• Accessible design requires making products
easier to use for everyone
– Who doesn’t like that?
Good Grips
Fred and Ginger
• Accessible technology often requires creative
technical solutions
– Mainstream products may benefit from these solutions
DEKA
Design principles
(Web Content Accessibility Guidelines 2.0)
1. Perceivable
Ensure that all content can be presented in form(s) that
can be perceived by any user - except those aspects of
the content that cannot be expressed in words.
2. Operable
Ensure that the interface elements in the content are
operable by any user.
3. Orientation/Navigation
Facilitate content orientation and navigation
4. Comprehendible
Make it as easy as possible to understand the content and
controls.
5. Technology Robust
Use Web technologies that maximize the ability of the
content to work with current and future accessibility
technologies and user agents.
More principles
• Present information in a clear and straightforward
manner
– Limit large amounts of text
– Structure documents clearly
• Express ideas in multiple media when possible
– ALT text for HTML images
– Transcripts for audio/video content
• You don’t need to sacrifice visual style for
accessibility
Types of disabilities
• Visual
– Blindness
– Low vision
– Color blindness
• Hearing
• Motor skills
• Cognitive disability
– Reading disorders
– Attention disorders
– Memory impairments
Blindness
• User cannot see visual content
– Pictures, diagrams, animations, etc.
• May use a screen reader to get information
– Cannot scan a page quickly
– Must navigate linearly through text
• Solutions
– Provide structure to text for easy navigation
– Add text or audio descriptions to images/video
– Follow standards for maximum compatibility with screen
readers
Low vision
•
Many types
– Poor vision quality
– Partially occluded vision
•
Very common in seniors
•
Low-contrast text difficult to read
•
Solutions
– Allow font resizing
– Allow color schemes to be changed
– Add text or audio descriptions to images/video
Low vision
• Many types
– Poor vision quality
– Partially occluded vision
• Very common in seniors
• Low-contrast text difficult to read
• Solutions
– Allow font resizing
– Allow color schemes to be changed
– Add text or audio descriptions to images/video
Color blindness
• Inability to distinguish between certain colors
– Affects 10% of males
– Often have problems with red and green
• Solutions
– Allow color schemes to be changed
– Don’t differentiate on hue alone
• Saturation
• Value
• Shape
Color blindness
What you see
What color-blind users see
visibone.com
Is this accessible?
Big Fish Games
Better
PopCap Games
Hearing impairment
• User cannot hear audio content
• This one is easy to test for
– Turn off your speakers!
• Solution
– Provide captioning for all audio content
Impaired motor skills
• Difficulty using mouse and keyboard
– Inaccuracy while clicking
– Slow input
– May use specialized input device
• Solution
– Do not require precise clicking
– Allow alternate input methods
• Keyboard
• Mouse
• Voice
Color blindness tools
• Will send these out later
Resources
• Dive Into Accessibility
– http://diveintoaccessibility.org/
• Web Content Accessibility Guidelines 2.0
– http://www.w3.org/WAI/GL/WCAG20/WD-WCAG20-20020424.html
• How People with Disabilities Use the Web
– http://www.w3.org/WAI/EO/Drafts/PWD-Use-Web/
• UMass Disability Services
– http://www.umass.edu/disability/
• Assistive Technologies Center
– http://www-pcco.oit.umass.edu/assistive/assistive.html