Color vision deficiency

You may not be able to see all the text or figures on this website. I have not yet checked all pages for color vision deficiency (CVD) yet, while in fact quite a lot of people have some form of color vision deficiency. The following is based on information mainly from J-fly, an organisation involved with drosophilia melanogaster genes and therefore in need of preparing many colored images, which all people should be able to see.

How many people have colorblindness?

•The frequency of colorblindness is fairly high. One in twelve Caucasian (8%), one in 20 Asian (5%), and one in 25 African (4%) males are so-called "red-green" colorblind. It is commoner than AB blood group.

How could it affect your work related to disaster risk management?

•There is a good chance that the paper you submit may go to colorblind reviewers. Supposing that your paper will be reviewed by three white males (which is not unlikely considering the current population in science), the probability that at least one of them is colorblind is whopping 22%! 

•People reading your publications or website cannot see all your text or figures.

•Flood Hazard Maps or other (disaster) maps cannot be read by all of the target audience.

•The audience of your presentation may not see what you are indicating on the slides, or when you use a red laser pointer. 

How does it work and what do people see?

What can you do?

•Choose color schemes that can be easily identified by people with all types of color vision. 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 (see the example below).

•Clearly state color names where users are expected to use color names in communication.

•Avoid indicating objects only by color name. Make it possible to communicate without using color name. Describe shapes and positions.

•Use a green laser pointer, it works for both color blind and non-color blind people.

•Use a website to check if your images are visible: http://www.vischeck.com/examples/ (this site is currently down, please let me know a suitable alternative)

•Test how your website appears to colorblind people: https://www.toptal.com/designers/colorfilter

•Test yourself for colorblindness types: http://www.testingcolorvision.com/

Sources:
http://jfly.iam.u-tokyo.ac.jp/color/
http://www.visibone.com/colorblind/
http://msdn.microsoft.com/en-us/library/bb263953(v=vs.85).aspx
http://www.colourblindawareness.org/colour-blindness/
wikipedia