green

Colour me blue, or green, or anything you like.

Prof. Brian Cox’s recent documentary series, The Planets, on our solar system neighbours was brilliant though short and sweet. It’s on the iPlayer for the best part of a year so watch it if you can. It’s mind boggling and it makes me think how could there possibly be life anywhere else. As for humanoid aliens, especially ones which speak fluent English with American accents, no chance!

As I watched it n the BBC app, it threw up some other suggestions I might like and one of those is a documentary about colour. I watched two episodes and it’s okay, maybe a bit superficial scientifically but entertaining and well produced (link below).

The funny thing about colour is it probably doesn’t exist. Or, I should say, it didn’t exist until life developed eyes. And not all eyes: the earliest eye probably only distinguished between light and dark; then there are eyes which only see in monochrome shades. Even the human eye is limited, only able to detect light within the band known anthropologically as visible light. Only some critters, it is thought, see beyond that.

And even within the so-called visible light, different people see different colours. This idea came home to me this week when I was looking over a drawing with a colleague. It showed a floor plan of a building where each of the rooms was coloured corresponding to its use. A key to the side of the drawing explained what each colour meant bit there were so many room uses that some of the colours were indistinguishable at a glance.

My colleague pointed to a room and said it wasn’t clear what kind of room it was; it could, he said, be either one or other shades of green. This struck me as odd. I couldn’t determine which type of room it was either but to my eyes the colour was definitely one of the two shades of blue.

Admittedly it wasn’t lapis lazuli, more the colour of a clear morning sky with a little pollution. But it wasn’t green, no way. Or was it?

I had an odd notion that I could reproduce near enough the exact colour by mixing primaries, blue, red and yellow – pigments, not light, of course. But then the colleague would agree it was mixed perfectly, but he would still see it as green.

So, remember, when we’re visited by those little green men from outer space, they might actually be blue. Or, quite possibly to their eyes, deep x-ray-ultraviolet.


image (top): No. 61 (rust and blue) by Mark Rothko

Colour: The Spectrum of Science (BBC TV)