Christmas Camouflage and why you shouldn’t copy anyone’s slides without thinking first

Three years ago I blogged about how ‘Tis the season for Christmas Camouflage in graphics. About ten percent of men, and thus five percent of people are red-green color blind. To them both Santa and his elves look like they joined the army and (as is shown above for deuteranopes) are wearing almost identical olive drab uniforms. Changing the image to gray scale reveals that the brightness for Santa’s suit is very similar to the elves. If you thoughtlessly use red and green with similar brightness in images, then you confuse and lose those 5%.

What’s it like to be color blind? In his autobiography Models of My Life  a famous university professor, Herbert A. Simon, described a childhood memory:

“....Whether during his fourth summer or on some later occasion, the boy was among a party picking wild strawberries. The others filled their pails in a few minutes; there were only a few strawberries in the bottom of his. How could the others see the berries so easily amid the closely matching leaves? That was how he learned that strawberries are red, and leaves green, and that he was color blind.”

In my senior year I had him for a psychology course, and never learned that he was color blind. Six years later, while his title was Professor of Computer Science and Psychology, he won the Nobel Prize in Economics. After he died in 2001, one of his colleagues, Omer Akin (professor of architecture), reminisced that: 

“Over the 27 years that I have known him, and hundreds of encounters with him, I never saw him angry except for perhaps once and for a brief moment. I had plotted out some results of the chunking experiment that I had done with architectural subjects. I brought in the piece of paper with me to our meeting. He looked at it and his face changed. I thought at that moment that there was something wrong with my data or its analysis. He said ‘You people never think of the color-blind.’ “

In December 2013 Angela Martin blogged about Now you see it, Now they don’t: Designing for the color blind. There is a more detailed discussion of Color Universal Design here.
 
A post by Matteo Cassese on December 16, 2014 in his La Fabrica Della Realta blog discussed Why I love tech presentations but hate these 5 mistakes. Near the end he recommended reading Garr Reynold’s book, Presentation Zen (as do I) and said:

“When in doubt, copy Garr’s slides.”

Please don’t do that without thinking. Some of Garr’s examples have red-green problems, like the one shown above from page 136.

In 2009 I blogged about another example he used in his blog (shown above), where a salmon color and green also were indistinguishable if you were a deuteranope. Everyone has his blind spots, and this is one of Garr’s.