What is a pixel anyway? pix·el (pĭk’səl, -sĕl’)
n. The basic unit of the composition of an image on a television screen, computer monitor, or similar display. And how does it differ from film grain?
A pixel, as you can see above, is the unit of measurement for digital. Film grain is an actual physical thing, whereas a pixel is a representation of something, usually on a computer screen, or your digital camera LCD screen. Screens are rated by their number of horizontal and vertical pixels; for example, 1024 x 768 means 1024 pixels are displayed in each row, and there are 768 rows (lines).
Short for Picture Element, a pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousands (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected.
The number of bits used to represent each pixel determines how many colors or shades of gray can be displayed. For example, in 8-bit color mode, the color monitor uses 8 bits for each pixel, making it possible to display 2 to the 8th power (256) different colors or shades of gray.
On color monitors, each pixel is actually composed of three dots — a red, a blue, and a green one. Ideally, the three dots should all converge at the same point, but all monitors have some convergence error that can make color pixels appear fuzzy.
The quality of a display system largely depends on its resolution, how many pixels it can display, and how many bits are used to represent each pixel. VGA systems display 640 by 480, or about 300,000 pixels. In contrast, SVGA systems display 800 by 600, or 480,000 pixels. True Color systems use 24 bits per pixel, allowing them to display more than 16 million different colors.
Basically, the more pixels you have in an image, the higher quality the output. I don’t know that digital can ever be as good as film, but we’ll see. As of right now, you will still get a better picture from a film camera than you will with a digital camera. That is because film captures so much more information than current digital media can.