Scanners: The Beginner's Guide
Just a few years ago, computer scanners were reserved for the rich and famous. Most of the more common models were expensive and difficult to operate, and were usually only found in the graphic design and print shops; what use would the average layman have for such a device?
These days, however, scanning hardware has been increasing in popularity and decreasing in price. With the advent of flatbed scanners, home computer users all over the world are putting pictures of their pets on the Web, making their own birthday cards, and scanning important documents onto their hard drives. Scanning software is easier to use than ever, and scanners are so inexpensive that many computer manufacturers are adding them to the list of peripherals that they include with mail-order computer systems.
But what about those of us who don't know a scanner from a can of Spam? What about those of us who would love to e-mail a photograph to Aunt Edna, but just don't know where to begin? You've come to the right place.
Scanner Types
If you are buying a scanner for use at home, you will probably want to buy a flatbed scanner, in which the document that is being scanned lies flat across a glass surface similar to that of a copy machine. There are cheaper scanners into which photographs can be inserted and far more expensive ones which utilize mystical technologies like photomultiplier tubes and rotating glass drums, but for home use, a flatbed scanner is almost always the best choice.
Resolution
I could go on for an hour about the details of optical and interpolated resolution, but I won't bore you. Suffice it to say, it is a good idea to look for a scanner with at least 300x300 dpi resolution. Dpi stands for "dots per inch" and refers to the amount of pixels that a scanner picks up in a square inch of a scanned document. For example, if you are scanning a photograph of your Cat, Chloe, with a 300x300 dpi scanner, the scanner's sensors will convert each square inch of Chloe into a 300 pixel-high by 300 pixel-wide block. Most scanning software will allow you to specify the scanning resolution, however, so you don't need to scan Chloe at quite so precise a resolution if you don't want to.
Some scanners try to impress you with promises of "interpolated resolution," but take it with a grain of salt. Interpolated resolution means that the scanner doubles its resolution by "guessing" what every other pixel should look like based on the pixel on all four sides of it. This isn't a good idea for pictures with a lot of color, however (like photographs). Since photographs are what most home users scan, avoid using interpolated resolution.
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