Tuesday, February 25, 2014

Color - It's All In Your Mind!

Colors exist in very much the same way that art and love exist.  They can be perceived, and other people will generally understand you if you talk about them, but they don’t really exist in an “out in the world” kind of way.  Although you can make up objective definitions that make things like “green”, “art”, and “love” more real, the definitions are pretty ad-hoc.  For example, green is light with a wavelength between 520 and 570 nm.  However, to some folks, art may be a portrait of Elvis on black velvet backdrop, and love might be the smell of napalm in the morning.

These kinds of definitions merely correspond to the experience of those things, as opposed to actually being those things.  For example, there is certainly a set of wavelengths of light that most people in the world would agree is “red.”  However, that doesn’t mean that the light itself is red, it just means that a Human brain equipped with Human eyes to label it as red.

When a photon (light particle) strikes the back of the eye, whether or not it’s detected depends on what kind of cell it hits and on the wavelength of the light.  We have three kinds of cells, which is pretty good for a mammal, each of which has a different probability of detecting light at various wavelengths.  One of the consequences of this is that we don’t perceive a “true” spectrum.  Instead, our brains have three values to work with, and they create what we think of as color from those.

However, some animals have different kinds of cone cells that allow them to see colors differently, or see wavelengths of light that we don’t see at all.  For example, many insects and birds can see into the near-ultraviolet which is the color we don’t see just beyond purple.  Many birds have ultraviolet plumage, and many flowering plants use ultraviolet coloration to stand out and direct insects to their pollen.

In the deep ocean most animals are blind, or have a very limited range of color sensitivity (after all - what is there to see?).  But some species, like the Black Dragonfish, have taken advantage of that by generating red beams of light that they can see, but that their prey can’t.

It may seem strange that some creatures are just “missing” big chucks of the light spectrum, but keep in mind; that’s all of us (people and critters alike).  The visible spectrum (so called, because we can see it), is the brightest part of the Sun’s spectrum.  Since it’s what’s around, life on Earth has evolved to see it.  But, there is a lot more spectrum out there that no living thing comes close to seeing. 

What’s more interesting is that when we as humans see the color of something, we are actually seeing the color that is bouncing off of it.  So in essence, since the object is absorbing every single color except for the one that you are seeing - the object is actually every other color BUT the one you are seeing.  So a red apple is every other color except for red (since red is bouncing off). So the fact remains, color itself is only real and true because our eyes send messages to our brain to see them that way.

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