The Basics: Scanners

A scanner's job is simple: It converts a physical photo or document into a digital version that you can manipulate on your computer. Scanners are great for archiving old photographs in a digital format that will never fade, converting print documents into digital word processing files that can be edited and even compiling and organizing business cards. At their core, scanners haven't changed much over the years, but they've become much more refined devices, capable of crisp and accurate reproductions.

Most scanners are traditional flatbed models with a large footprint. While these can occupy a considerable chunk of desktop real estate, the design makes it easy to flip up the lid and scan even legal-size documents. Flatbed and photo scanners used to be separate devices, with the latter being much smaller and offering higher resolution and color depth to handle photographs. However, specifications for flatbed scanners have increased while the cost has stayed the same, and most new photo scanners are simply high-resolution flatbeds.

Sheet-fed scanners are small models that feed a document or photograph through the thin, compact body of the scanner to capture an image. These are less popular than they were a decade ago, but they're still around. Sheet-fed scanners are more portable, but they don't usually have the same resolution or versatility of the full-size flatbed scanners.

Speaking of portability, pen scanners have become more prevalent in recent years. These scanners can either scan text one line at a time or, in some of the newer models, scan entire documents or images in a single pass. They're extremely easy to carry around, but you need a steady hand to capture an accurate image.

The power of a scanner is in its optical resolution, rated in dots per inch (dpi). Most new flatbed scanners offer resolutions of 2,400 dpi or higher, which means that you'll be able to recreate a photograph accurately. The specs on the scanner box also talk about color depth or bit depth. This number refers to the amount of color that can be added to each pixel of an image. Greater color depth means more realistic images, and most new scanners offer color depths of 24-bit or higher (currently up to 48-bit).

One thing to keep in mind with scanners is that creating high-resolution scans consumes a lot of resources, including hard drive space. If you're going to be scanning numerous full-size images, make sure you've got a computer with the power and the space to handle them.

How to Shop

Obviously, the kind of scanner you should buy depends on your scanning needs. If you have a variety of items that you will be scanning, it's best to go with a traditional flatbed scanner. Most flatbeds have adjustable lids that let you scan 3-D items such as magazines, bound books and other objects. They usually have the highest optical resolutions, so you'll be able to create the sharpest scans. And they're often less expensive than non-traditional scanners.

However, not all flatbeds are created equal. Budget flatbed scanners have maximum image sizes of 8-1/2x11-7/10 inches, which is large enough to scan letter-size documents. If you need to scan legal-size documents, you'll want to spring for a flatbed scanner with a larger scan area of 8-1/2x14 inches.

Flatbed scanners aren't for road warriors, as their design requires them to stick close to a desktop computer. If you've got scanning needs attached to your portable computer, you'll want to take a look at a sheet-fed or pen scanner. Some sheet-fed models use new low-power CIS (Contact Image Sensor) technology and don't require an external power source. They get their power through a USB connection, so that's one less accessory to pack. Pen scanners may not offer as high of optical resolution as flatbed scanners, but they're extremely portable.

Once you've settled on a category of scanner, you can start looking at the extras. Many flatbed models offer an optional transparency adapter, and some even have one built in. This add-on device lets you scan in film negatives and slides, creating full-size images from your small originals. If you're going to be archiving a lot of old photo negatives, a transparency adapter (or at least the option to add one in the future) is a must.

Some flatbed scanners ship with automatic document feeders (ADF). If you perform a large volume of scans, an ADF makes it easier to stack up photos or documents into a tray that then feeds them into the scanner one at a time.

Other scanners have quick-use buttons that let you quickly perform an action, such as e-mail an image, send it to a printer to make a copy or create an Adobe Acrobat PDF document from your scan. These can be handy for quick tasks, saving you the time to open up the scanner software.

Older scanners used to feature parallel port or SCSI connections. Most new scanners connect to your computer via a USB 2.0 cable (which is also backward-compatible with USB 1.1 ports, although scans will be slower), which makes installation a simple task. However, some scanners might also have a FireWire connection for Macintosh or portable computers. Check to make sure you have a compatible connection before you purchase the scanner.

There usually isn't a huge difference in scan speeds between brands of scanners. However, if you're looking to do high-volume scans, you might want to consider a scanner that can work quickly as well as accurately.

The software bundle that ships with a scanner is another important deciding factor. Two important applications bundled with a scanner can include image editing and organizing programs and optical character recognition (OCR) software for inputting a text document to a word processor. Other extra applications may be included, such as applications that let you upload your scanned images to a website for sharing with friends and family or software that repairs and restores scratched or faded photos. Check to see how robust a bundle your scanner has to make sure it comes with all the software you will need.

Consumer scanners can be quite inexpensive, starting at well under $100. If you're a basic home user that just wants to archive your vacation pictures, you'll do fine with one of these budget flatbeds. Business users or digital photo enthusiasts might want a more expensive scanner that offers higher resolutions, a larger scanning bed or extras such as an ADF or transparency adapter. Regardless what your needsare, you can find a scanner with the format and features to meet them.