Tuesday, 22 November 2011

Stupid Questions

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"
Needless to say my response at this point was delivered in full and frank Anglo-Saxon language.


  1. Your Maternal grandfather would have suffered from the same colour-blindness: although he may not have ever realised that there was anything wrong.

  2. Hi BF, I have a friend who has a similar condition, in that he sees in shades of grey! A bright red note book with black marker pen writing on the front and he can't see the writing! But he's worked out a method of getting around this sort of thing - he tilts the book until the letter catch the light and reflect a sheen - then he reads the sheen!

  3. @Anon1 I'm not aware he did, but it could be possible as it's hereditary as you suggest. It didn't stop him building parts of Spitfires though :-)

    @Anon2 Cheers for your comment - always ways round these things. The ingenuity of being British.

  4. Must be a claim for you there for visual handicapism !

  5. Now its funny you mention those bloody ishihara plates because I had exactly the same problem at school If I squint long enough I can just make out the number 21, but even then it's sort of blurred.

    As you rightly point out, its trying to differentiate between the different shades of a colour rather than distinguishing between the different colours that is the problem.

    Love your blog btw - I frequently use your quotes on the right hand panel. Very useful for shooting down EU lovers.

  6. @Pete ha perhaps I should give it a go?

    @rapscallion Agreed, there's many of 'us' about. Many thanks for your kind comments as well about my blog.

  7. I have exactly the same colour blindness as you by the sounds of it.
    Its the light shades of yellow/green that confuse the heck out of me.