Lately, I’ve been wondering why we predominantly write with pens that have inks in two colours: blue or black. I remember that in school we were explicitly told not to use green, purple, or heaven-forbid, red pens. The penalty was death. I’m kidding, the teachers only caned us.

I remember that the school principal used to use a green coloured pen to sign letters or late slips or whatever. That green seemed exotic at the time.

I think teachers didn’t want you to write in red because they evaluate answer sheets with their own red pens and the colour clash can lead to confusions.

What I don’t get though is why we’re asked not to use any of the other colours. Green is a perfectly fine colour to use, so is violet, maybe even brown. I’ve never tried the latter two, so I don’t know.

I did buy red and green refills a few weeks ago and I started using the green one, but I had to change to blue. I was afraid that someone would use the green pen without knowing and accuse me of ruining a cheque leaf or whatever else.

Which brings me to my second point. I get why schools — whose job it is to get you ready to conform — would restrict the colour of pens that you can use. Why is there the same restriction in the real world? A form that I came across recently had instructions that told you to use blue ink only. And, in my various forays into the real world, corporate or otherwise, I can’t remember a single time that I’ve seen a pen with green or a purple coloured ink being used. I’m not kidding.

I can make a case for not using red because it’s associated with danger (traffic signal for example) but why not green or any of the other reasonably dark colours? I’m not asking for yellow and pink pens because I think that they’ll be hard to read on white paper, but brown, purple, green, maroon — they’re all colours that can be read.

If you know the answer or have a theory about why we use only specific coloured inks, feel free to chime in. I’m stumped.

Some research after the fact

After I finished writing this post, I went to Google and found this article. It explains why blue ink is preferable on legal documents — it contrasts with the black print. Another point made, in a different place, was about copiers and scanners and how certain colours don’t copy or scan well.

Interestingly, there’s a lot of discussion on this topic but I haven’t come across any definitive answers.