Consumers buying a scanner to digitize images can choose from a wide range of economical options. But this can also make shopping for a scanner confusing for novices. Here is a short primer.
Buying a Scanner: The Basics
Whether buying a flatbed, document, or large-format scanner, there are some basic criteria to consider. Resolution and color depth are the most important, as they directly affect the quality of scans.
Scanner resolution is measured in dots per inch (dpi) or pixels per inch (ppi). The higher the number, the more detailed the scan. However, manufacturers often tout the interpolated resolution of scanners, which uses software to boost scan resolution artificially. Optical resolution is a better indicator of a scanner's quality (much like the difference between digital and optical zoom on digital cameras).
Color depth refers to the amount of colors a scanner can identify and output, measured in bits per pixel. 24-bit color depth (16.7 million colors) is the low end. Most scanners are 48-bit, with some topping 96 bits. Color depth, like resolution, becomes increasingly important if scans are to be enlarged.
Since scanners transfer images to a computer, the quality and ease-of-use of a scanner's included software and drivers is also an important consideration when buying a scanner. Most scanners come with some form of photo-editing software too.
Buying Flatbed Scanners
The most common scanners are flatbed scanners. Since the material to be scanned is placed loosely on a plate of glass, flatbeds can accommodate a wide range of media, from receipts to books – even artwork. Although flatbeds are the most versatile kinds of scanners, they generally take up the most space.
Flatbed scanners are also incorporated into multifunction or all-in-one printers, which can be excellent buys for those who regularly print and scan. However, flatbed scanners on multifunction devices tend have lesser quality, and, with smaller scanning beds, can only accommodate one letter-size sheet at a time.
Buying Document Scanners
Businesses that mostly scan letter-sized documents may find dedicated document scanners to be more economical than flatbeds. Similar to a fax machine (and sometimes including fax capabilities), these scanners automatically feed sheets through as they scan.
Document scanners have the advantages of speed and convenience, especially when doing batch scans. They often take up far less desk space than a flatbed scanner too. However, document scanners also have disadvantages: they can't scan stapled documents or books, and often only scan in low-resolution black and white.
Buying Slide Scanners and Large-Format Scanners
There are a number of types of scanners of particular interest to artists and photographers.
Film or slide scanners are specially designed for converting old slides and negatives into digital images. Professional-quality slide scanners are bulky and expensive. But they produce the best results, as slides need to be properly back-lit during scanning.
There are also cheaper slide scanners for home use, but these produce inferior results. Many cheap slide scanners aren't really scanners at all, but specialized digital cameras with slide mounts.
Some flatbed scanner models now have slide mounts which allow them to scan slides and film negatives as well as documents. But as with cheap slide scanners, these don't create archive-quality scans.
Large-format scanners are flatbed or sheet-fed scanners that can accommodate sheets larger than 11 inches by 17 inches. Due to their size and extra cost, they are not for home use. Large-format scanners are mostly used professionally to digitize artwork or technical drawings for manipulation or retouching on a computer.
Which Kind of Scanner is Best to Buy?
Above all, consumers should keep in mind what they need a scanner for. Those who require general-purpose scans would do best with a flatbed scanner, either as a standalone model or as part of an all-in-one printer.
But professionals buying a scanner may find that a specialized model, such as a document scanner, slide scanner, or large-format scanner, fits their needs better than a flatbed.
Luke Arnott - Luke Arnott has a Master's Degree in Comparative Literature from the University of Western Ontario, where he is currently enrolled in the ...
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