So what is a pixel?

Might as well start at the beginning. Luckily, my professor for "Digital Production Process" (DPP) thinks so, too.

A pixel, derived from "picture element" (a quasi-portmanteau), is the smallest unit that comprises a digital image. If you were to take a photograph and lay a sheet of grid paper over it, each square would be a pixel--although your photograph wouldn't look so great in a computer. That's because computers run on binary code (0 and 1), where 0=off and 1=on, so your pixel would either be black or white. To get around these 2 options, we then break down each option into two again (0, 1), and again, and so on, creating shades of gray until we reach 2^8 power, or 256 shades. At 256, the human eye can no longer distinguish between each shade, so the progression from black to white looks like a continuous scale. This is the minimum for the illusion, also called 8-bit graphics, which progresses upwards to 16-bit, 32-bit, etc. The higher you go, the better the quality of the image. The same holds true for the number of pixels in an image: the number of pixels across by the number of pixels high equals the image resolution. We see these kinds of numbers when purchasing digital cameras or adjusting our computer monitor resolutions; my computer is set at 1200 x 800 pixels and 32-bits.

Fun fact: The story goes that the Pixar name is yet another portmanteau for "pixel art." This is, however, untrue. Here is the version I was given by Alvy Ray Smith, who co-founded the company and whom I interviewed for my "Rat" thesis:

"I grew up in New Mexico with Spanish all around. The verb infinitive in Spanish ends in '-er,' '-ir,' or '-ar.' I proposed to Rodney Stock and Loren Carpenter and Jim Blinn one day over burgers that we name our new digital optical printer with a name that, like 'laser,' was a noun that looked like a Spanish verb. I proposed 'pixer' as in, 'to make pictures.' Loren, or perhaps Rodney (Loren says it was he), said that the word 'radar' was very high-tech sounding, so what about spelling it 'pixar.' I immediately agreed because that is another Spanish word form...So the name of our device became the Pixar (or Pixar Image Computer). When we were looking for a company name, we just couldn't decide on one...We were called simply the Computer Division at Lucasfilm because we could never decide on a sexy name like 'Industrial Light & Magic.'...Finally, in desperation because we needed a name for our company documents, I said, "Well, the word 'Pixar' is now associated with us, so why don't we call the company that?' Everyone groaned, but said unenthusiastically, "Welllll, okkkkkk" [sic]. So I can justly claim that I named the company, but as you can tell it was not greeted with rousing cheers at the time."