1) The document discusses making designs and information accessible for people with color blindness, as about 8% of men and 0.5% of women experience some form of color blindness.
2) It provides steps to test for color blindness, ensure computer displays accurately show colors, and test designs using color blindness simulators.
3) Guidelines are presented for using high color contrast, avoiding sole reliance on color to convey information, and choosing colors that are distinguishable to those with common types of color blindness.
7. We perceive what we expect.
Our perception is biased by our
experience, the context, and our goals.
“In visual perception a color is
almost never seen as it really
is[…] This fact makes color the
most relative medium in art.”
Joseph Alberts, Interaction of Color, 1963
9. 99% of all colorblind people are redgreen color blind
"Red-green" color
blindness is observed
among one out of twelve
Caucasian (8%), one in
20 Asian (5%), and one in
25 African (4%) males.*
* http://jfly.iam.u-tokyo.ac.jp/color/
11. Why does that matter?
1 in 12 men (8%)*
* NHS Choices
1 in 200 women (0.5%)
12. Step 1: Test if you are color blind
Take the online test:
http://www.color-blindness.com/ishihara-38-plates-cvd-test/
What People With
Regular Vision See
*.Ishihara Test for Color Blindness
What Red-Green
Color Blind People See
13. Step 2:
Test if your computer is color blind
Test for computer color accuracy
http://goo.gl/lJi5bk
Example:
*.Ishihara Test for Color Blindness
14. Step 3:
Test your design for color accessibility
• Colorblind Simulator
http://aspnetresources.com/tools/colorBlindness
• Colorblind Web Page Filter
http://colorfilter.wickline.org/
• Vischeck
http://www.vischeck.com/vischeck/vischeckImage.php
• Accessibility Validation in Photoshop
• WAVE
http://wave.webaim.org/
• Sim Daltonism (for Mac)
http://michelf.ca/projects/sim-daltonism/
• Contrast-A: Accessible Color Combinations
http://www.dasplankton.de/ContrastA/
15. Print a copy of the screen in black
and white to verify color is not the
only way to identify or distinguish
information.
*. IBM Software Accessibility Checklist
16. Step 4:
Follow the color accessibility guidelines
• Web Content Accessibility Guidelines (WCAG) 2.0
Guideline 1.4 : http://www.w3.org/TR/WCAG20/#visual-audio-contrast
• Your company‟s Software Accessibility Checklist
• Color Universal Design Organization (CUDO)
http://jfly.iam.u-tokyo.ac.jp/color/
18. Example:
Choosing the wrong colors
for a chart can make it
literally unreadable for a
colorblind user.
6
4
2
Series 1
Series 3
Add a little pattern or texture
to different parts of a chart to
make for easier visual
differentiation.
6
4
0
2
0
Series 1
Series 3
25. Avoid the situation where texts and
objects are obscured with the
background.
Hi There!
Non colorblind
Deuturanopia-type
26. Keep the number of colors to a
minimum
Use combinations of different symbols with a few, vivid
colors rather than a single symbol with various colors.
30. Avoid color-specific instructions
Click the green button to
purchase!
Label your buttons clearly and
reference them in the site copy
by function, not color, to avoid
confusion.
Amazon.ca
31. • When color customization is
supported, provide a variety of color
selections capable of producing a range of
contrast levels.
32. Related resources from WCAG 2.0 guidelines :
•
•
•
•
•
•
•
•
•
•
Lighthouse International: Effective Color Contrast
Vischeck
Internetworking: Designing for the Color-Challenged: A Challenge
AWARE Color Laboratory
Colorblind Web Page Filter
Firelily Designs: Color Vision, Color Deficiency
Wikipedia: Color Blindness
Microsoft: Can Color-Blind Users See Your Site?
BT Inclusive Communication: Choosing safe colours
Causes of Color: How do people inherit colorblindness? How often?:
Genetics
• How to make figures and presentations that are friendly to
Colorblind people
• The Color Tutor application
When you think of the color “red,” think about how many completely different color samples could match your definition of red.
How about the Coca-Cola Red?
That’s the exact same ‘RED’!
Red appears more brilliant against a black background, but lifeless against an orange background.
Colorblindness is actually a decreased ability to see color, or a decreased ability to tell colors apart from one another. A colorblind has only two different color receptors (cones) compared to three with normal color vision.
Don’t rely solely on color - Avoid the situation where important information is conveyed only in the form of color.
For color-coded text, use bold fonts such as ArialorHelvetica, rather than thin Times.
It’s safer to use a symbol cue like the asterisk which is color-independent.
it’s always better to add something else visually in addition to color shifts. So if you switch colors on a hover, make sure the two colors are very different in their relative brightness. You can switch from a dark brown to a bright green, just not from a dark brown to a dark green. Keep contrast not only in hue but also inbrightness.
For example, red characters on green backgrounds is unreadable for colorblinds. Use either bright texts/objects over dark backgrounds, or vice versa.
be sure to reference the name of the color in the description of the product.