Alt means alternative text. A look at how to write it, thinking about audience, content, context.
These slides are from the Accessibility Summit, 2014. Register for access to recorded sessions:
http://environmentsforhumans.com/2014/accessibility-summit
3. Alt text is...
A principle of accessibility
Web Content Accessibility Guidelines 2.0
Principle 1: Perceivable
Information and user interface components
must be presentable to users in ways they
can perceive.
4. Alt text is...
A requirement for accessibility
Web Content Accessibility Guidelines 2.0
Guideline 1.1 Text Alternatives: Provide
text alternatives for any non-text content
so that it can be changed into other forms
people need, such as large print, braille,
speech, symbols or simpler language.
5. Alt text is...
Code.
Specifically, an attribute in the image element
<img src="tickets.jpg" alt="#A11YSUMMIT. Buy tickets">
6. Alt text is...
Part of appealing to all senses.
Images – alternative text
Video – captions and video descriptions action
Audio - transcripts
An accessible UX principle:
Accessible Media: Appeal to all Senses
A Web for Everyone by Sarah Horton and Whitney Quesenbery
http://rosenfeldmedia.com/books/a-web-for-everyone/
7. Because technology needs it
Screen readers (and other assistive
technology) can't interpret the meaning
of the image without it.
<img src="fb.jpg">
<img src="twitter.jpg">
<img src="li-logo-square.jpg">
<img src="g.jpg>
<img src="btn1875412.jpg"
8. Because people need it
People who use
screen readers
and other AT
When images are
missing or turned
off
For translations
Jacob Vishnu
Trevor Maria
Personas from A Web for Everyone by Sarah Horton and Whitney Quesenbery
http://rosenfeldmedia.com/books/a-web-for-everyone/resources/
10. Alt text is invisible content
It's hard to tell if it's good or bad...or
even it it's there.
Even bad alt text passes
accessibility checkers.
Banner Ad
<img src="banner-ad-176987362334876292.jpg"
alt="banner-ad-176987362334876292.jpg">
11. Is it code or content?
Who "owns" the alt text?
Developers
Art directors
Authors
12. The tools don't help
It's no fun to
1. find each image
2. click open the properties sheet
3. navigate to the right page
4. to enter the alt text
over and over and over for each image
13. Or they get in the way
They ask for the information at the
wrong time, and in the wrong way.
14. The usual rules
A simple way to decide how to
write alt text
15. The simplest guideline
Start with this question:
What information does this image
add?
Does the page make sense without
it?
What kind of information is it?
16. If the image contains
Text Repeat the words
Visual information Explain it
Sensory information Describe it
Nothing new Ignore it
<img src="useless image" alt="">
17. A simple decision tree
What is the role of the image?
Decorative? Use null alt text or CSS
Sensory? Write a descriptive identificaation
Informative?
No new info? Use null alt text
Simple or a link? Write short alt text
Complex image? Create long text
Section of the same page
Linked page
Longdesc
4 Syllables - http://www.4syllables.com.au/2010/12/text-alternatives-decision-tree/
18. Or, a detailed analysis
HTML5: Techniques for providing useful text alternatives (updated Sept 8, 2014)
http://rawgit.com/w3c/alt-techniques/master/index.html
19. On the HTML5 standards horizon:
<figure> and <figcaption>
Keeps the image, alt text, and
caption together
<figure><img src="castle-painting.jpg" alt="The castle
now has two towers and two walls.">
<figcaption>Oil-based paint on canvas. Eloisa Faulkner,
1756.</figcaption></figure>
Example from: http://rawgit.com/w3c/alt-techniques/master/index.html#m6
21. 1. Know your audience
What knowledge or background do
they have?
What terminology will they know?
<img alt="Molecular structure of
diethyl diazenedicarboxylate">
22. 2. Context, not just rules
What is the reader's goal?
How does the image fit into the
page?
What other information is around the
image?
23. 3. Create a consistent 'voice'
Make the alt text part of the (stylistic)
voice of the site, in how images are
voiced (by assistive technology).
Functional?
Descriptive?
Emotional?
24. Consider the fox
What should the alt text for this image be?
Image Credit: J. and K. Hollingsworth/USFWS
25. What if we see it on this page?
The text on page shown in the image says
Red Fox (Vulpes vulpes)
Description
Red foxes are a rusty reddish color on the upper side of their body and tail. They have a white
underside, chin and throat. Their tail is very bushy with a characteristic white tip, and they have
prominent pointed ears. The backs of the ears, lower legs and feet are black. Other than the
common rusty red, red foxes have three different color variations: a black phase where they are
almost completely black, a silver phase in which they are black with silver-tipped hairs, and a
"cross" phase where individuals are reddish brown with a dark cross across their shoulders. Adults
typically stand 15 to 16 inches from the ground and are 35 to 41 inches in length. They can weigh
between 8 and 15 pounds.
26. Or on this one
The screen shows 3 images with this caption:
From left to right: 1. Monarch butterfly on a
New England aster, credit: Greg
Thompson/USFWS 2. Red fox, credit: John &
Karen Hollingsworth 3. Eastern brook trout,
credit: USFWS Click image for full-size.
28. Get the basics right
Repeat the text in the image.
Alt text: “Webcast. Applying 21st Century
Toxicology to Green Chemical and Material
Design. September 20-21, 2011”
29. Get the basics right
Identify the target of a link
Alt text:
“UXPA group on Facebook”
"@UXPA_Int on Twitter"
"UXPA's LinkedIN profile"
30. Don't create noise
When images are used like a bullet,
they can have empty alt text.
If they are clickable make them part of
the text link.
31. Don't hide meaningful images
Is a profile photo part of the content?
<img alt="Photo of Caroline">
or
<img alt="Caroline Jarrett">
32. Make captions and alt text work
together
The caption:
“Birnbaum, right, joined Collins at front
stage as she accepted a Director’s
Award on behalf of employees
honored for their contributions to the
Deepwater Horizon Gulf Oil Spill
Response. (Photo courtesy of NIH)”
The alt text:
“NIEHS/NTP Director Linda Birnbaum,
Ph.D. accepts award from NIH
Director Francis Collins, M.D., Ph.D.”
33. Don't hide information in the alt text
Caption: Red fox, credit: John & Karen Hollingsworth
Alt text: Red Fox as Sachuest Point NWR. Credit J and K
Hollingsworth
34. Don't just repeat the same text
Caption and alt text both say:
Gerald Chan is an alumnus of the public health school,
having earned master’s and doctorate degrees in the 1970s
35. Consider the surrounding text
The caption:
“Figure 1: The ABC of research
methods”
The alt text:
“ABC diagram.”
or
"ABC diagram sketched on a
chalkboard.”
or
“A diagram sketched on a
chalkboard as a triangle. Top:
Attitude. Right: Behavior. Left:
Comprehension.
36. When the text is long...
Put the text on the
same page, and link
to it.
The alt text:
“Two personas"
The caption includes a link:
“Read the text in this image”
The text is in a box at the end
of the article.
The caption reads: Example snapshots of
personas demonstrate Spanish-speaking
users’ language needs and preferences, as
well as medical literacy, web skills, and
other relevant characteristics. Read the text
in this image."
The link points to a grey box below
37. When the information
is in a chart...
Combine the visual
chart with a data table.
The alt text:
"Bar chart of data in table below"
The title:
"More Education Means More
Money"
http://www.careerinfonet.org/finaidadviso
r/earnings.aspx?nodeid=21
38. When the text is in an infographic..
Design the infographic in
HTML and CSS so the
text is text.
Not as easy to do, but a
better experience for
everyone.
http://simplyaccessible.com/article/text-is-text/ and
http://apps.washingtonpost.com/g/page/national/the-health-hazards-of-sitting/
750/
40. How long should alt text be?
No more than a few words?
(WebAIM)
5-15 words?
(Many sources)
30-50 words (2-3 sentences)?
(W3C Draft)
41. Keep it short
Focus on the important words (no
prizes for writing long prose).
Avoid noise words
"Image of.. "
"This is a..."
42. Be consistent
Each image, each page, each section
is all part of your site or app.
Use the same approach everywhere,
especially for functional elements:
Providing additional text
Locating explanatory text or data
Identifying figures in the text
43. Add alt text to the writing workflow
Write the text, caption, alt text together
Hiding the image in the manuscript makes it
easier to visualize the flow of the words.
This is the text in the image:
...mall, we realized that even everyday items such as clothing and shoes would
also be bought in installments (see Figure 1). A light bulb went off for us—not
only was it common to pay in installments, but it applied to items we did not
expect, too.
Alt text: Picture of shoes with installment pricing sign
Figure 1. In a mall in Sao Paulo, our research team spotted more items sold in
installments than we initially expected. Notice that the installment price is
more visually prominent than the total price!
44. This is change!
Admit it
Embrace it
Set a reasonable pace
Rome wasn't built in a day
(but if you don't start, you never get there)
45. Make the web a better
place.
Write some (great) alt text today!
46. Storytelling for User Experience
with Kevin Brooks
Global UX
with Daniel Szuc
A Web for Everyone
with Sarah Horton
http://rosenfeldmedia.com/books/a-web-for-everyone/
47. Get in touch!
Whitney Quesenbery
whitneyq@civicdesign.org
@whitneyq
http://civicdesign.org
@civicdesign