Web design for color blind users

Presented byRajalekshmy UshaHCI assignment 412/11/2001

Color Blindness Hereditary genetic disorder Afflicts 8 percent men and 0.5 percent

women Most services and companies use no or

less consideration for this group. For example, some instructions say “press the red button” Color coded pills Red warning and green safety light on some

machines

Types of Color Blindness Red-Green Color Vision Deficiency:

Most commonly referred to as “color vision deficiency” since the sufferers are not entirely blind to colors

Total Color Blindness: Rare, but is present across all ethnic groups Two types:

•Typical : complete failure to discriminate colors•Atypical : low color sensitivity, only clear colors

detected

Statistics and facts on color blindness Approximately 10 million people in United States are blind

and visually impaired At least 1.5 million blind and visually impaired Americans

use computers (source :American Foundation for Blind) Males are more prone to color blindness 7 percent males and 0.4 percent females suffer from red-

green color blindness

A Simple Color Blind Test A normal person

sees a 5 revealed among the dots

A red-green color blind person sees a 2 revealed in the dot

How a normal person sees the world

How a person with red-green color deficit sees the world

How a person with blue-yellow color deficit sees the world

Web Design Analysis Most of the current web designers give

little or no consideration for color blind users

Not willing to sacrifice minor design elements for the majority of the users

However popular web sites are simple and not overloaded with colors

Examples of web-sites with poor readability http://www.moviephone.com/

Light orange background in the left navigation menu

Different color links with green and orange which blends in

http://www.wired.com/: garish colors too much even for normal users Red and green backgrounds are kept

together

Examples of web-sites with good readability http://www.amazon.com/

Simple and elegant Used distinct colors for menus, images etc No red and green colors together

http://www.hotmail.com/ The butterfly icon may not be that distinct

http://www.whitehouse.gov/: Again simple and plain but fonts on the menu tab could have been

larger

My Goal for this Web Design

Make internet accessible to color blind users

Provide an opportunity for web-designers, system developers and for all society

Acid Test on the readability of color combination

-Represent worse-case scenario since the fonts are small and thebackgrounds are highly saturated-Brightness of the font increases from top to bottom andthe brightness of the background increases from left to right- I will use this color swatch for web designing

Use ALT = ‘…’ text for all the images. Use JavaScript Mouse over events to describe

the status event description of all the images Use blue, yellow, white and black to really

distinguish items Provide numerous links with a text version , if

you cannot do without graphics Provide labels next to any colored indicators Emphasize important with larger fonts, color

highlight(proper ones!) and outlining boxes Provide visual cues like icons or arrows if there

are no underlining for text links

My web design guidelines for color blind users

Click on the red button Next

My web design guidelines for color blind users - 2

Provide strong contrast between background and the foreground colors

Effective and non-effective hue contrast is shown in the picture alongside.

What are not allowed …DON’T : Use red/purple/gray/brown/green next to or to

the top of red/purple/gray/brown/green Use various shades of one color Use single light bulb that changes color from red

to yellow or green to yellow under any circumstances

Use colors in images to denote special areas, such as bar charts, maps, and navigation bars

Overload the web site with large number of visually striking buttons, garish colors and extreme imageries.

A A A A A

A A A AA

hotel phone water( good format )

(email icon - bad format! )

DON’T : Use decorative , complicated or cursive fonts

• Roman typefaces are effective

•Decorative typefaces are not effective• Condensed typefaces are not as effective• Sans serif type faces are effective

Extensive use of italics – oblique or condensed

• Upper and lowercase of a typeface is more readable• Italics and bold types are not as effective

What are not allowed …2

Interface Designs to be considered Give information feedback by giving

instructions, which refers to objects e.g. “press the button marked “ON” or “wait for the light on the left”

Strive for consistency throughout while designing the websites

Do regular usability testing – it provides opportunity for revision and improvement

Compactness and branching factors of web page

Conclusions Black and white works best Never solely rely on colors Enhance each use with an image, shape,

positioning or text Use bright colors – they are easiest to tell

apart Use the appropriate back ground so you can

make even the less safe color visible E.g. red against white, green against black,

turquoise against black, magenta against black.

Internet Resources for Web design for Color Blind Users : www.firelily.com/opinions/thumb.html http://www.firelily.com/opinions/color.html www.vischeck.com http://newmanservices.com/colorblind/default.asp http://members.aol.com/nocolorvsn/color5.htm http://www.visibone.com/colorblind/ http://trace.wisc.edu/world/web/