17. Straight talk on buying a
Translating DPI, OCR, ADF
By Mark Alberstat
OVER THE PAST decade, the most popular add-on for any home or business
computer has been a scanner.
A few years ago, it was an expensive
proposition, often costing over $500, and you would need a technician or
someone well-versed on the insides of a PC to install a special connector
board that allowed the 13.5-kilogram scanner to talk to your 22.5-kilogram
That was then, this is now. Scanners can now be seen by the pallet load at
wholesale stores. They're also bundled together with new PCs for those who
want all the bells and whistles when they order their new Dell, Compaq or
other brand-name computer.
If you are in the market to buy a scanner, you may be overwhelmed when you
go shopping. There are different types of scanners in various price
ranges. All have a variety of numbers and letters attached to them,
creating a complex alphabet soup of information on the scanner box or from
DPI is one acronym you will hear lots when scanning the market. It simply
means dots per inch, and most scanners today will feature 1,200 or 2,400
DPI. This is fine for almost all uses. Anything higher gets you into the
professional realm and out of most practical budgets.
If you find a deal on a scanner that has fewer than 1,200 DPI, walk away.
It may be cheaper, but in the long run the quality of scanning you may
want to do will just not be available. One caveat, however, is that the
higher resolution at which you scan and image, i.e., the higher the DPI
rate, the larger the images will be. That is something to keep in mind if
hard-drive space is limited.
OCR is another popular acronym and an important one if you plan to scan
documents you want converted into text you can later manipulate. OCR
stands for Optical Character Recognition, a fancy bit of software that
recognizes scanned text and can save it to a text document. Many scanners
do not come with OCR software and you would have to buy it separately,
adding to the overall cost of your setup.
If you scan a lot of text pages, an automatic document feeder, or ADF, may
be a consideration. This extra bit of hardware can save users a lot of
time opening and closing the scanner to change pages. Some scanners will
have ADF as a standard feature while others will offer it as an add-on.
Most scanners on the market today are flatbed scanners, so named because
they feature a large glass panel on which you lay your photo or document.
Other scanner types are hand-held or sheet-fed. The sheet-fed ones look a
lot like ink-jet printers. You place your document where the blank paper
would go in a printer.
The software that comes with the scanner is the bundle that allows the
scanner to talk with your PC or Mac. Most of this software is relatively
straightforward to install, and hooking the scanner to your PC usually
involves nothing more than two cords. One gives the scanner power while
the other runs from the scanner to one of your computer's USB ports. (For
more information on USB, see this past column.)
With this knowledge in hand, you are now prepared to enter the world of
scanner shopping. Shop around and find what you want.
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Originally published 14 September 2003