What?! Yeah, I know. It’s all one big lie, played on each and every one of us by our own bodies. Let’s take a look at the color spectrum:
Do you see any pink in there? No? That’s because it’s not a color of the visible spectrum. (Though you can search on the internet and find people who display the color indigo as pink… which doesn’t make any sense as it’s in between blue and violet. For this to make any sense at all we should probably briefly discuss how we perceive color to begin with, because when I look at something pink it certainly looks like a color to me! (and right now you’re thinking… yeah looks like a color to you because you’re an IDIOT LOLLOLOLOLOL).
Perception of Color
When you look at something, you are observing the light that reflects off of it. If I shined a white light (white because it is the sum of all colors in the visible spectrum) onto say an apple, the apple would absorb much of that light, the light that isn’t absorbed is reflected of which then reaches your eyes. The colors of light that reflect off of that apple can be described in terms of wavelengths between 640 to 760 nm (which are various colors of red) Citaton. Maybe you are looking at a green leaf attached to that apple, well the chlorophyll in that leaf absorbs light and the light that reflects back is why you see that green color. It’s actually interesting to see a plot of what light chlorophyll is absorbing:
The two types of chlorophyll in leaves look to absorb lots of red and blue colored light, not shockingly all of those wavelengths that aren’t absorbed and reflect back at you are green.
Detection of Color with Your Eyes
So all of that light reflecting off of things and reaching your eyes enters inside through your pupil and strikes cells called cone cells, which come in three flavors (short, medium and long, yes I know those aren’t flavors, deal with it):
So the graph above is of the wavelengths of light that the cells can perceive, short cone cells see blueish light, medium cone cells see greenish light and long cone cells see redish light, when light strikes these cells they signal to your brain, hey hey I am detecting something here!! Your brain then interprets that signal (based upon its strength) into what we call “color.” You will note that we can only actually perceive three real colors (red, green, blue), but we see a variety of other colors. For instance yellow, it’s a real color of light, but we can’t directly see it, we perceive yellow when both our long (red) cones fire strongly and medium (green) cones fire more weakly the same time (this is because yellow is a wavelength of light just shy of 600 nm, and if you look at that wavelength on the plot above for our cones that’s about the max of the red curve and on the downside of the green curve.)
So wait… Doesn’t That Mean Pink IS a Color?
Yes, It’s not a REAL color of light, but it is still a color (you can relax now, seeing those pink elephants is totally natural after all!). Pink is actually a compound color, we see it when all three of our cones are firing simultaneously, the long cone must be firing strongly, while at the same time the medium and short cones must be firing just a little bit (aka there is no one wavelength of real light that can make that happen)! It takes a combination of wavelengths of light to activate our eyes in such a way that our brain assembles pink.
Sources:
http://www.popsci.com/science/article/2012-03/metaphysics-color-and-defense-pink
http://www.livescience.com/32559-why-do-we-see-in-color.html
https://en.wikipedia.org/wiki/Cone_cell