The Almighty Pixel
Open a picture file in your favorite graphics editing software, such as Photoshop, Paint Shop Pro, or Fireworks. Just about any picture file will do - could be .GIF or .JPG, .BMP or .PICT, .TIFF or .PNG. Use the zoom tool and zoom in on part of the image. Then do it again. And again.
Do you notice the way the image loses more and more definition as you get closer and closer? The way the smooth curves and contours give way to straight lines and right angles? The way the softly blended shades and hues become nothing more than tiny blocks of single colors? Allow me to introduce you, dear readers, to the pixel.
Just about anyone who works with computer graphics is familiar with the pixel; what it is, what it looks like. But what is a pixel, really? How does it work? Where does it come from? What are its mating habits?
The word "pixel" is a playful combination of the words "picture element," and it basically refers to the smallest possible single unit of pure color on a computer screen. Pixels were called pels way back when monitors were newfangled and Tron hadn't been invented yet, but these days if you ask someone what a pel is, they'll tell you it's the name of a Teletubby. A pixel's size is actually not a physical, measurable thing as some might believe - actually, the size of a pixel depends on what it applies to, just like the time it takes you to get from your house to the store down the street depends on how fast you are going. A picture that displays on your computer screen as three inches high by three inches wide might be composed of only a few thousand pixels, or it may be made up of millions of them - it all depends on the resolution (how many pixels make up each inch of the image).
You can't measure a pixel?
Not as such... what you can measure is the dot pitch of your monitor. Dot pitch refers to the physical "dots" of light that make up the display on your monitor and is measured in millimeters. If you have a monitor with high resolution, you might have one pixel mapped to one dot. A lower resolution will mean that multiple pixels are mapped to each dot and your picture won't be as sharp.
How many pixels wide is my monitor?
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