Red-green color blindness
I’m red-green color blind. I know this not only because I regularly fail color vision tests, but because of my own experience with colors. I’m not sure if everyone experiences this difference the same way , so I can just report on my own observations.
Being red-green color blind does not mean I can’t see the color red. I can. It doesn’t mean that I can’t see the color green. I can. It doesn’t even mean that I can’t distinguish a red light from a green light. I can. It means that I can’t distinguish some shades of red from some shades of green and that I can’t distinguish some shades of both colors from shades of grey.
How does this difference affect me? In many ways. Let’s consider some examples.
One of the textbooks that I use highlights text in dark green. It took me a half semester of teaching with the textbook to realize that there was highlighted text in the book. I wrote to the publisher to suggest that they make different choices in the future. I’m not sure if they did.
Recently, I’ve been working with SIGCSE student volunteers. The SIGCSE Student-Volunteer Management System has a little symbol that is supposed to indicate whether or not a volunteer has checked in. Green means
checked in. Red means
not checked in. But the symbols are otherwise indistinguishable. Of course, I had to be told this. I had no idea that we were using the symbols to mean anything, since they looked identical to me. I didn’t even notice that there was a symbol there, since it served no purpose in my mind.
I even attended one youth soccer match in which I couldn’t tell the teams apart. I think they were dark maroon and something close to dark forest green .
None of these are earth-shattering problems. But they all made my life a little bit harder and they all irritated me. What really worries me, though, is what red/green issues I don’t know that I’m missing. Have I been ignoring prompts throughout my life? I have absolutely no idea .
Is my red-green color blindness one of the reasons I’m a bit aggressive about accessibility issues on campus? Perhaps. If my relatively minor disability causes some problems and frustrations, I can only imagine the roadblocks the world puts in the way of people with more serious disabilities.
Postscript: My children joke about my red-green color blindness all the time. They old up a green apple and say
Isn’t this a beautiful red apple? They point to a shirt and ask
Why is this Grinnell shirt green? But they know that I can tell what color it is .
 I’m not even sure if everyone experiences color the same way. How do we know that the way I experience
blue is the same as the way you experience
 No, the teams were not sponsored by the University of Chicago and Dartmouth.
 Of course, I miss prompts all the time, whether or not they have to do with my color blindness.
 Most of the time.
Version 1.0 of 2018-03-10.