What is flat and indispensable at the office, and isn't a credit card? A flatbed scanner. It's easy–to–use and enables users to replicate and send documents, photos, book pages, and business cards to a computer desktop, email address, or Web site — often with the touch of a single button.
One of the most important features of a scanner is its bit depth. Put simply, the higher the bit depth, the richer and more accurate the scanning. This is especially true when the image (such as a photo or intricate graphic) being scanned has sharply contrasting shadows or abutting colors of different tones or hues.
Scanner bit depth starts at 24 and goes to 32, 36, 42, and 48. If you want to scan slides, negatives, or transparencies, opt for a scanner with a bit depth of at least 32 or 36. People looking for stunning color representation should consider a bit depth of 42 or 48.
Along with bit depth, optical resolution is the main determinant of how well a scanner will capture the full color quality of an original. Resolution is measured in dots per inch (dpi). The following table details the optical resolution range of flatbed scanners, and notes the suggested uses for each.
|Resolution (in dpi)||Total number of dots (color and black and white) per square inch||Recommend for:|
|300 x 600||180,000||Scanning text|
|1200 x 1200||1.44 million||Scanning text, photos, and graphics|
|1600 x 3200||5.12 million||Scanning text, graphics, and photos that will remain the same size and/or be enlarged|
|2400 x 4800||11.52 million||Scanning graphics and photos that will be enlarged as well as architectural plans with fine lines|
Manufacturers often list a scanner's interpolated resolution, which describes the number of artificially generated dots the scanner inserts between scanned dots to smooth out the image and to reduce uneven lines when enlarging. You should concern yourself with interpolation only if you plan to enlarge graphics or photos. If you do intend to do a lot of enlarging, look for an interpolated resolution of 9600 dpi.
Flatbed scanners are typically equipped to scan letter–size originals (8.5"x11"). Scanners that list 8.5"x14" as a maximum document size can also scan legal–size documents.
If you're in the market for a scanner, you might want to consider a multifunction machine instead. A multifunction machine saves money (and desk space) by combining several functions into one machine. A 3–in–1 multifunction machine is a printer, copier, and scanner; a 4–in–1 is all of these plus a fax machine; and a 5–in–1 is all of these plus a computer fax.
Many multifunction machines are equipped with a flatbed (rather than a sheet–fed) scanner, and some models have a bit depth and resolution that are just as good as a stand–alone scanner. Click here to read frequently asked questions about multifunction machines.
There are specialty scanners designed for nearly every need. Film scanners are specially designed to scan 35mm slides and negatives (both color and black and white).
Business card scanners — perfect for those who travel often for sales or to meet with clients — are small and ideal for scanning business cards and transmitting contact information directly to a computer or handheld (PDA).
Bar code scanners, depending on the model, can read bar codes from 1.5 inches to as far as two feet away and are used to manage inventory, audit shelf prices, gather purchase data for marketing, and to ring up customers at the point of sale.
Click here to learn more about these different varieties of scanners.