I’m a bit colourblind. It only affects certain ranges of colours. I first realised this when I got a Vic-20. No, really. The default screen colour was white, and the default border colour was cyan.
I thought cyan looked like green. People tell me it’s really a light blue, indeed I remember reading an interview with some Commodore engineers who had debated about whether to call it light blue or cyan.
There were eight colors available; white, black, red, cyan (light blue), purple, green, navy blue, and yellow.
In real life my colourblindness is so mild it only seems to affect one thing: spotting the numbers in Ishihara tests.