Once a big-ticket item, scanners are becoming very affordable. For as little as $99, you can buy a letter-size flatbed scanner that can convert text, photos and drawings into computer documents you can edit, print, post on the Web or e-mail to friends and family.
Scanners aren't the only way to get pictures into a PC. Digital cameras, which are also coming down in price, not only let you skip having to pay to buy and develop film, they connect directly to your personal computer so you can see a photograph almost immediately.
But they have limitations. They won't let you digitize photos taken on traditional film, and unless you spend big bucks, the results won't be as good as a conventional photo scanned into your system.
Scanners, on the other hand, can be used for more than just pictures. They can turn printed pages into computer files and capture electronic images of receipts and other documents, which can then be stored conveniently in digital bits.
Scanner makers usually grade their products by two factors. The first is resolution, expressed as dots per inch. If you see a scanner billed as "300 by 600 dpi," that means the scanner senses resolutions of 300 dots per inch horizontally and 600 as it scans down the page.
The second factor is bit density (typically 24, 30 or 36 bits). The bit number indicates the subtlety of color or shading the scanner can detect. For example, 24 bits translates into more than 16 million colors or shades of gray and 36 bits into more than 69 billion. Experts debate at what point the human eye ceases to distinguish such gradations, but they agree that the more shades or colors, the more accurate the image.
Numbers, however, don't tell the entire story. The quality of a scanner also depends on its software drivers, the applications that come with it and its overall design. Speed can also be a factor. In general, scanners that connect to a PC or Macintosh via an SCSI interface are about 50% faster than those that connect via the printer port. But they'll work only if the host computer has an SCSI card, with which all Macs are equipped but which are only an option even on many high-end desktops.
How you use a scanner can also have a big impact on the quality of the image. Scanning at too low a resolution, say 100 dots per inch, can yield fuzzy images. Yet scanning at high resolutions not only takes longer but uses much more disk space. An uncompressed 1-square-inch scan at 600 dpi takes up roughly a megabyte of disk storage, while the same image at 200 dpi takes up about 120K. If you don't plan to enlarge an image that you're printing out on a high-quality inkjet printer, you'll get optimal results at 200 and 300 dpi, according to Tim Daughters of Storm Technology. "Anything higher than that," he says, "is absolutely overkill."
If you plan to double the size of the image, you should increase the resolution accordingly, Daughters said.
Storm Technology makes two excellent letter-size, low-cost flatbed scanners, starting with the $99 ImageWave, which scans at a resolution of 300 by 600 dots per inch. I used it to scan several snapshots and was impressed at how well they looked on screen and on paper.
Storm has also just introduced a $149 TotalScan model with a resolution of 600 by 1,200 dpi. Storm products connect to a PC's printer port but have a pass-through port so you can still use your printer. Neither works with a Macintosh.
Several companies make more expensive scanners that connect to a PC or a Macintosh via SCSI interface. The Umax Astra 1200S, which costs about $250, is an excellent 600-by-1,200 dpi, 30-bit scanner. The Epson Expression 636, a 36-bit, 600-dpi model, is even better, but at about $800, it's too expensive for most home and small-business applications.
When evaluating scanners or digital cameras, pay attention to the bundled software. Most inexpensive scanners and cameras come with some type of low-cost and easy-to-use image-editing programs like Adobe PhotoDeluxe or Microsoft Picture It. Higher-end devices typically come with professional editing tools like Adobe PhotoShop.
Just about all scanners come with photo-editing software, and some also come with optical character-recognition software (OCR). This is software that helps you turn printed pages into electronic text. Personally, I almost never use OCR because just about every periodical I read and most of my mail comes via the Internet. If I want an electronic version of an article, I download it.
Lawrence J. Magid can be reached at email@example.com