1. Web design for color blind users Presented by Rajalekshmy Usha HCI assignment 4 12/11/2001

2. 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

3. 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

4. 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

5. 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

6. How a normal person sees the world

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

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

9. 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

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

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

12. 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

13. Acid Test on the readability of color combination - Represent worse-case scenario since the fonts are small and the backgrounds are highly saturated -Brightness of the font increases from top to bottom and the brightness of the background increases from left to right - I will use this color swatch for web designing

14. 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

15. 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.

16. 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 AA A A A A A A A AAA A A AA hotelphonewater ( good format ) (email icon - bad format! )

17. 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

18. 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

19. 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.

20. 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/