Friday, November 26, 2004
When shopping for a scanner, you'll want to look for a few important things. Here's a quick summary.
- Resolution: Scanners generally have a lot more resolution than you need, measured in samples per inch (spi). You'll also see terms dots per inch and pixels per inch applied to scanners, even though scanners don't have dots (printers do) or pixels (monitors do). Scanner resolution varies from 600 x 600 spi to 2400 x 2400 spi, or higher. Unless you're scanning tiny, very high resolution originals (such as postage stamps), anything more than 300 to 600 spi is overkill.
- Color depth: This is the number of colors a scanner can capture. The color depth is measured using something called bit depth. For example, a 24-bit scanner can capture 16.8 million different colors; a 30-bit scanner can grab a billion colors, and a 36-bit scanner can differentiate between . . . zillions of colors. You'll never have an original with that many different hues, however. In practice, the extra colors simply provide the scanner with an extended range (called dynamic range) so that the scanner can capture detail in very dark areas of the image as well as in very light areas.
- Speed: Some scanners are faster than others. If you're scanning a lot of photos, you'll want one that works quickly.
- Convenience: So-called "one-touch" scanners have buttons mounted on the front panel so that you can trigger the scanner to make a copy (that's sent to your printer), scan to a file, route a scan to e-mail, capture text with optical character recognition, or perform other functions.
- Bundled software: The best scanners are furnished with an easy standalone software interface plus a more professional scanning program that gives you total control over every scanning function. You also get drivers that let you access these interfaces from within programs, such as Photoshop. You may even get Photoshop (or a "Lite" version) bundled with the scanner, plus software to create panoramas, build Web pages, manage documents, and do other fun stuff.
- Accessories: Some scanners include sheet feeders (for scanning a stack of documents) or can be fitted with them as an option. Others have slide-scanning attachments or built-in slide-scanning tools. Depending on the kind of work you do, these accessories can be a perk or a necessity.
