I’m working on an experiment with Adam Sparks on how people read maps. As a part of the experiment, we wanted to assess whether people were colourblind. I thought we could use something like an ishihara test to assess this. You might have seen this plates before, they look like this: The idea being that if you are not colourblind, you can identify a number or letter in these plates, and if you have colourblindness, you cannot identify the number (which should be …