"Yo listen up, here's the story About a little guy that lives in a blue world And all day and all night and everything he sees is just blue Like him, inside and outside....."
After having somewhat of a revelation regarding colour theory after reading up about primary colours recently, I’ve been delving into some of the history and mystery surrounding colour itself. Today…. I’m Blue (da be dee) - If you don’t know that ear worm of a song from 1998, from which the quote above comes, circulating in your head now, I’m offering it to you now. Sorry. Not Sorry.
Blue is, according to a number of assorted surveys, most people’s favourite colour. Associated with two of the Earth’s most prominent natural features, the sky and the water (also technically not containing any type of pigment to make them blue), it is interesting to note that early humans may not have even been able to perceive the colour blue. Some scientists think that our colour perception has evolved over time with us starting as only perceiving black, white and red, then later yellow and green, then blue after that. Now, whilst we are sitting around here in our indigo-blue jeans and loving it across the board, how isn’t Mother Nature big on blue?
Let’s start with water and sky. These contain no pigment to make them blue. The sky appear blue because as white light from the sun (which contains a full spectrum of all colours) hits our atmosphere it is scattered in all directions. Blue light has the shortest wavelength, so it is scattered the most and we see it more. You’ll notice that as the sky gets closer to the horizon it is lighter and may even appear white. That’s because the light particles have scattered so many times, and have started reflecting back from the Earth’s surface so much that the colours recombine to more white.
There are not many blue animals and plants. In fact, with only a few exceptions there are virtually no animals or plants that carry a true blue pigment. Most birds, insects and flowers we see as blue appear blue to us because of tricks of the light rather than actually carrying blue pigment themselves. For example, the blue feathers of birds are caused by the physical structure of them. The keratin structure or microscopic texture of the feather scatter the light, the red and yellow wavelengths cancel out and the blue ones reflect and amplify. the effect is that we see blue. It works similarly for most blue insects, who’s wings have tiny scales which operate with the same effect.
And guess what? People who have blue eyes also actually have no blue pigment either. It is also a structural, optical illusion. The stroma (the front of the iris or coloured part of the eye) is actually colourless in blue-eyed people. The blue colour is cause by white light entering, then being scattered back by the colourless stroma into the atmosphere, similar to the way we end up seeing water and the sky as blue.
Flowers and plants appear blue by making a slight modification to the far more common red anthocyanin pigment. Again, the pigment is not a true blue at all, blue appears to us through a modification of structure.
I’ll discuss how we actually make blue paint in another post, in the meantime, I’ll just be leaving you with the bombshell that in nature at least, despite it being most people’s favourite colour, blue hardly exists.