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Friday, July 31, 2009

What's In A Color?

What's in a color?
Okay, now that I've drawn you in with a quirky question....   We all take a lot of things for granted in our daily lives. One of those things is color. Do you really know what it is?

Here are some thoughts about color that will hopefully make you think, and maybe encourage you to take a few less things for granted.

What's the color of this post background? What's the color of that wall in front of you? Are these two questions only about 2 different objects? Nope, and here's why. First, let's assume that the "answer" to both questions was Blue, just for argument's sake. Now, you're seeing the post background on your computer screen. Your computer screen (assume standard CRT screen/monitor) displays an image due to electrons being shot from the back of your monitor that hit the back surface of your screen and excite the pixels (picture elements) to produce that Blue color. The blue color you see are the blue photons (packets/particles of light) emanating from the excited pixels. Interject another question here for later reference: Is "Blue" a property of the post background, or at least a property of the blue part of the screen you are seeing?

As to the wall, well,.... you are seeing blue because that is the color of the light that is being "Reflected" from the wall. The wall is actually absorbing all other visible colors, but reflecting blue photons to your eyes. Is "Blue" really a property of the wall? Upon reconsideration, is it accurate to simply call the wall Blue? Or, the color of the wall Blue? Or, would it be more accurate to say that the wall is not really Blue, but rather that the wall has the property of reflecting blue light? Or, since the wall is absorbing everything but blue, shall we say it is every color but blue?

So, big deal, am I simply trying to make a mountain out of a molehill of semantics? I'm hoping that a little further reflection (pun intended) on your part will result in a better appreciation for what Color is or is not.

But I'm just getting started here, don't dis out on me now!

The light we see with our eyes is technically called electromagnetic radiation. And, "Visible" light is just a very small portion of the whole band, or spectrum, of electromagnetic radiation. Bees can see ultraviolet light - we humans can't. It's wavelength is too short for us to detect - it's shorter than that of visible light. This is sort of like dogs being able to hear sounds with higher pitches (smaller wavelengths), like dog whistles, than we can. If we could see things as bees see things, we'd see a vastly different world around us!

Radio waves are electromagnetic radiation - just like visible light except that it has a wavelength too long for humans to see. Infrared is electromagnetic radiation too, but it also is too long of a wavelength for us to see. The only difference between all the forms of electromagnetic radiation is the wavelength involved. Humans can only detect/see a very limited range of electromagnetic radiation. All the different colors we can see are simply different wavelengths of light.

The image below serves two purposes: 1) it gives you an idea of just how small the visible light spectrum is compared to the entire electromagnetic spectrum; 2) it gives you an idea of the relative sizes (wavelengths) of commonly known types of electromagnetic radiation in terms of things we are familiar with - from waves that are as long as a football field to waves that are smaller than an atom.
Curious fact: the infrared light that is furthest from the visible light range is called far infrared, or thermal radiation. Yup, that's just simple heat! Warm objects give off thermal radiation - infrared. It's still electromagnetic radiation, folks - light that we humans can't see. But the technology of infrared night-vision equipment, commonly used by police and the military, detects thermal radiation and converts it to visible light that humans can see.

Now consider that there is a lot of that electromagnetic radiation, essentially light if you will, that is constantly passing straight through your body, through your house, through your car, through your office, etc. When you listen to an AM or FM station on your radio, the signals that your radio receives with it's antenna (the antenna may be external or internal out of sight) are simply a particular range of electromagnetic radiation. It's the same thing as visible light - you just can't see radio waves. Talk on your cell phone - EMR (electromagnetic radiation) waves are traveling through you constantly. Change the channel on the TV with a remote control - EMR again.

How many other things can you think of now?? Yep, your microwave oven, garage door opener, car key controls, walkie-talkies, wireless networks, satellite TV, etc., etc., etc.- EMR. You are being literally bombarded by electromagnetic radiation constantly!

Food for thought: What color is a mirror? What color is a clear pane of glass? A perfectly transparent pane of glass would be invisible to us since it would neither reflect any light, nor absorb any light.

Is black a color? We usually call something black if it absorbs all the colors rather than reflecting any. Or, if we happen to be looking up into the night sky at the blackness of space between the stars, black is the absence of light altogether and thus the absence of color.

Is white a color? We usually call something white if it reflects (or emits) all the colors rather than absorbing any of them. So, can we actually consider white to be a single color, unique from others? We experience it as a unique color, but is it really?

Curious fact: you'll get black paint if you mix all the primary paint colors together. If you mix all the colors of light together, you get white light. So, how do you get white paint? A prism splits all the colors of white light into its constituent colors - like the rainbow you see in the sky when water droplets in the atmosphere split the white light from the sun into all those wonderful colors.

So,.... What's in a color?????

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