The word PIXEL [pick-sell] comes from two words:

Picture = PIX and Element = EL. A pixel is the smallest part of a digital image. A digital image from a camera, a scanner, or as seen on your monitor is composed of thousands or even millions of pixels. If you have ever seen a ceramic design or image made up of hundreds of tiles (a mosaic), you should get the idea.

MONITOR PIXELS: The easiest way to understand a digital pixel is to inspect a white area of your monitor with a strong magnifier (go ahead – try it!).

Note that all colors on a monitor are represented by 3 dots in a triangle: red, green, blue (RGB). The various colors in an image are accomplished by illuminating these dots in a specified ratio. If you want WHITE, all 3 color dots are brightly illuminated the same amount. Colors other than white are created by illuminating one or two of the dots more than the other(s). To create a BLACK portion of an image, all 3 colors are turned OFF in that area.

DIGITAL CAMERA PIXELS: The pixels relating to a digital camera are similar. Keep in mind the image of the monitor above. The optical sensor in a digital camera that takes the place of the film is a mosaic of sensitive spots that receive light from the lens. An image from a digital camera is likewise composed of 3 colors for each pixel.

MEGAPIXELS: You can calculate the megapixels (millions of pixels) by multiplying the horizontal pixels by the vertical. For example, a digital image 1600 x 1200 pixels is referred to as a 2-megapixel image (1600 x 1200 = 1,920,000).

© 2004 Fred Hall