How you see color, part 3

So if light is just a wave of energy, how do we see color? How do we see at all?




You eyeball has specialized cells called cone cells. Cones come in three different types. Each type is sensitive to a different wavelength on the spectrum. The cones are usually referred to as short, medium, and long, often shortened to S, M, and L, for the length of the electromagnetic waves they sense.



You might think that the three types of cones must see red, blue, and yellow, the three primary colors. However, these colors don't really correspond nicely to colors. L cones, for instance, are sometimes referred to as red receptors. Actually, they are closer to green-tinged yellow. The other cones, likewise, do not easily match up with primary or secondary colors. As a matter of fact, cones' light perception varies from person to person. The different cones' are sensitive to overlapping ranges of light, which is what lets us sense the variations.



The genes for sensing visible light are carried on the X chromosome. That is why color blindness is more common in men, and why some women have an extra type of cone, which can allow them to see light beyond what is visible for most people.



In lower lights, different cells, called rods, sense light. Rods don't have much to do with color differentiation though.



Intensity and amount of light is what determines the saturation of color. Saturation describes how dark or pale a color is.



Once the cones – and to some extent, rods – have absorbed the light, the nerves send that information to the brain, which puts the information together to form the images that you see. Interestingly, the inside of the eye sees the image in front of you upside down, and the brain has to flip it back right-side up in order to be useful to you in navigating the world.

Microchips and photonchips

Earlier this week, Google celebrated the co-creator of the first microchip with one of their Google Doodles. A microchip is defined by Wikipedia as "an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material."




I'll be honest, I read that a few times, and all I got was tiny thingamajig with some tiny conductor thingies that makes computers and the like work. Computers, cell phones, and other digital products couldn't work without them. Various microchip-esque ideas came and went between 1945 and 1958, when the first working microchip was created by Jack Kilby. They have come quite a ways since then. Moore's Law states that (in the long term) the number of circuits that can be inexpensively fit on a microchip of equal size doubles every two years.



Now, a new advance may put Moore's Law in the past. A new chip is in development which manipulates individual photons of light, guiding them and also containing and initiating their interactions. These tiny pathways on a silicon chip represent a huge step towards a quantum computer. Is anyone else thinking about the wonders of tomorrow-land?

How You See Color, part 2

How You See Color, part 2

In my previous post, I described how color is made up of light, and things that appear to be a certain color are actually reflecting that color.

Those colors of light are part of the visible spectrum – wavelengths that the eye perceives. There are many other wavelengths that the eye does not perceive. The whole spectrum is referred to as the electromagnetic spectrum. The longest waves are radio waves, and their wave length is the size of a building. Smaller waves, going down the spectrum, include microwaves, infrared, then visible, followed by ultraviolet, x-ray, and gamma ray. The visible spectrum has the longest wavelengths in red, getting shorter as you traverse the rainbow down to blue and violet. That is why heat, or infrared, has the word red in it. It comes right before red. Likewise, ultraviolet is just slightly shorter in length than visible violet light.

Theoretically, waves could be as long as the universe itself or infinitely short. The waves can carry information, like radio signals. Light also can transmit information, as in fiber optical cables.

Some wavelengths can be damaging to humans, like UV or ultraviolet, which sunblock can help protect against. Some wavelengths cannot easily penetrate the earth’s atmosphere. This group also includes UV, as well as most microwave, x-ray, and gamma ray.

How you see color

The human eye sees a wide spectrum of visible light - black to white and blue to red. While the keys on a FunKeyBoard are several colors, the fact is, the light is colored, and the keys just reflect that light.




Sunlight, lamplight, headlights...This light is all more or less clear, or white to the eye. White light is actually a combination of all colors in the visible spectrum. You've probably seen a prism split that white light into a rainbow, displaying the whole spectrum of visible light separately. Rainbows work the same way, with water droplets acting as prisms.



When you look at something, you perceive its color - unless you are colorblind, or course. A FunKeyBoard has a red case. What that means in terms of how you see the color is that the material it is made of reflects the red light. The reflected light is the light your eyes take in. The FunKeyBoard's case actually absorbs all of the colored light except red.



The keyboad that is on my laptop is black. It is reflecting back none of the colors of visible light, absorbing all frequencies. In actuality, it is not a pure black, which would reflect no light at all. Theoretically, a black hole would be the best example of a real black.