Everybody Most people can name the seven colors of the rainbow: red, orange, yellow, green, blue, indigo and violet (ROYGBIV). Some people will argue about indigo, because it's halfway between blue and violet. Many rainbow images will not even mention Indigo (see below).
I guess Indigo is just there to make the mnemonic Roygbiv just a little easier to pronounce... 😏
One color is missing
But why does nobody ever raise the question about MAGENTA? Or Fuchsia, as more
botanically oriented people tend to say.
Try to match it to the spectrum above, I dare you! You will find out it just isn't there!!
I can hear some you smart asses think: "And what about purple?" Well, purple is considered a shaded hue of magenta, maybe a bit more towards violet (blue). But I'll have to admit.... purple is also a bit out of line, just like magenta.
What is Magenta?
If it's not just light with a specific wavelength, then what is it? Let's start by explaining some more, what it is NOT! Some people might argue is just a tint of violet or maybe red. But the shades and tints of violet, magenta and red are only close to each other near black and white. And that's the case for all colors.
Okay, so it's not just a bit different shade of violet or red. Let's have a bit more scientific look at it.
From a physical perspective magenta is really different from the color of the rainbow. While all colors of the rainbow relate to light with one specific wavelength, magenta does not. Magenta is a mixture of violet-blue and red light. It consists of light with both short blue waves and longer red waves.
And while all other mixtures of light add up in our eyes and brain as just another tint or shade of a rainbow-color, these colors do not. Violet-blue and red add up to magenta (or purple)!
When you think of it, this is actually quite extraordinary. Yellow and green light add up to yellow-green which is within the spectrum. Blue and green add up to turquoise or cyan, which is within the rainbow. And so do all other combinations, except magenta!!
My display is RGB, but my eyes are "MBG"
Artists - especially digital artists - are used to think in additive colors. Every color is a combination, an addition if you like, of Red Green and Blue (RGB). We express this in numbers: #FF0000 is red, #00FF00 is green, and thus #FFFF00 is red + green = yellow. And voila #FF00FF is red + blue = magenta. Everything seems so lineair and logical!
But actually we very smartly trick our eyes and brains into interpreting these colors. It goes too far to explain how exactly this works. But there's one more thing I'd like to tell you about this.
It's a bit scientific, but not too complicated to understand. It's about the sensitivity of your eyes (and brain) for colors. It's shown in the graph below.
The striking fact from this graph lies in the red line. It shows our maximum sensitivity for red lies with the red light wave. This is no surprise, of course. But it has a second maximum at the violet wavelengths! In fact we experience violet light a bit as red!
It actually seems we have a special sensitivity for red-in-combination-with-blue... which - as we just saw - is magenta! Our eyes are not sensitive for RBG but for "MBG", Magenta Blue and Green...!
This not only makes it quite plausible why we see magenta as a separate color. It also explains why we experience the colors in a continuous circle with violet and red connected by magenta.
Extra-spectral or imaginary
Scientist made up a complicated word for magenta and related hues; they say these colors are "extra-spectral", meaning they're not in the rainbow spectrum.
It actually means that these colors just exists in our brain, they're purely imaginary!
