Readers probably recognise the above picture as an Ishihara colour plate used to test for colour blindness. These were my nemesis at school. I was subjected to these more than most because I neither had perfect sight nor full colour blindness - just somewhere inbetween - something which completely confused my testers. ("but you must be one or the other"). For example (apparently) with the above plate if you have normal sight then 74 should be visible those with full colour blindness you may see 21. Me? I just see dots.
My problem was not trying to find tennis balls in the grass nor distinguishing traffic lights but subtle differences between certain colours. Now, this has never been much of a problem: it only ever really cropped up with some computer games, notably older versions of Pro Evolution Soccer, where it would choose the teams' kits and you couldn't amend them. Certain clashes of strip colours meant that whilst I could see the difference when the game was paused I couldn't pick out the teams when the game was in progress and the players were moving about. The result was that in those circumstances I got heavily beaten (well that's my excuse and I'm sticking to it).
Anyway, 'my eyesight problem' has cropped up this morning. I've been installing, for the company I work for, a new server monitoring software, which uses a really rubbish traffic light system to detect problems. Basically it gives a red alert for a major hardware failure, a yellow alert for a minor failure and a green alert for all ok. However the subtle differences between the shades of green and yellow that are used means that I find it difficult at first glance to differentiate between the two. This resulted in the following conversation:
- Him: "It's that one" (pointing to the yellow alert)
- TBF: "Oh right thanks, sorry I'm partially colour blind"
- Him: "How can you not see that?"
- TBF: "I just can't, sorry"
- Him: "But it's obvious it's yellow, how can you not see that?"
- TBF: "Sorry, not to me it isn't"
- Him: "Jesus, you're weird"