Look around before you choose a scanner Here is a primer on this intriguing yet puzzling gadget

Your computer

November 24, 1996|By Michael J. Himowitz

JUDGING by the questions that come in the mail, I'd have to say that the most intriguing and perplexing PC gadget on the market today is the scanner.

People know they can use scanners to get family snapshots into their computers and onto their Web pages, or turn paper reports into word-processing documents without retyping.

But they don't seem to know exactly how. So here's a little primer.

A few years ago, scanners were expensive specialty tools for graphic designers. Now they're stacked up like cereal boxes in computer stores with signs that say, "Take me home."

Some PC makers, including Hewlett-Packard, are building photo scanners into their machines, while others, including Compaq, are putting scanners in keyboards.

When you get down to the nitty-gritty, all scanners are digital cameras that turn paper images into a series of dots. Your computer translates those dots into digital ones and zeros that it stores in a file in your hard disk.

Once you've scanned an image this way, you can do all sorts of things with it.

If it's a photo, you can touch it up with a graphics program -- or turn it into something entirely new (put Aunt Edna's head on Uncle Ralph's body).

You can use the image in a word-processing or desktop publishing document, or put it on a World Wide Web page.

You can scan a printed document and send it to someone with a fax-modem. Or you can use Optical Character Recognition (OCR) software to turn the little dots into real text that a word processor or spreadsheet will recognize.

What's the best scanner for you?

It depends on how you want to use it and how much you're willing to pay for image quality and features.

You can buy a small hand-held scanner for as little as $200, a sheet-fed black-and-white model for $300 or so, and a color flatbed for $400 to $1,500.

The first thing to decide is whether you need a color or black-and-white scanner. If you want digitized color photographs for your Web site or the kids' graphics projects, you'll need a color model -- and you'll pay more for it. If you're mainly scanning documents for faxing or conversion to word-processing files, a black-and-white model will do the job for less money. Most black-and-white scanners can also turn color photos into gray-scale images.

At the bottom of the market, you'll find small, hand-held scanners with an image area about 4 inches wide that you drag over the paper manually. They're best for small graphics and logos. Next up on the chain is the popular photo scanner -- a small, mechanized box that can accept photos as large as 5-by-7 inches.

For full pages, you'll want either a sheet-fed or flatbed scanner. Each has its advantages.

Sheet-fed scanners use mechanical rollers to pass sheets of paper over the scanner head. They're relatively inexpensive and can take up surprisingly little space on your desk. The Visioneer Paperport that I use is actually housed in a 2-inch deep bulge on the back of my keyboard. The paper feeds through a slot on the front and comes out the top. On the down side, sheet-fed scanners can't be used with books or magazines. Most create black-and-white images only, and the quality of the scans they produce isn't as good as the output from a flatbed scanner.

A flatbed is a box about 11 inches wide and 15 inches deep that looks and works like a small copier: You put the paper on a glass screen and the scanner head passes beneath it. Because the original image is stationary, flatbeds are capable of better reproduction than other scanners.

Scanners connect to your computer in several ways. Better models require a Small Computer Systems Interface (SCSI) controller. Macintosh users already have one of these built in. If you have a PC, you'll have to open the case and install one -- a five- to 10-minute job. Some newer scanners designed for PCs plug into your serial or parallel port. Besides being easier to set up, they can be used with more than one computer.

With any type of scanner, you'll pay more for better resolution and color depth. Resolution is measured in the number of dots per inch that a scanner can record. The cheapest scanners might resolve only 200 dots per inch (about the quality of a fax), while high-end models with 1200-dot resolution are overkill for all but professional publishers. For home and small office work, a resolution of 400 to 600 dots per inch is just fine.

Be careful here. Manufacturers can use software to mathematically enhance image resolution, and they'll often advertise that figure. Look for a scanner's "optical resolution," which is the true measure of the hardware's capability.

Color depth is referred to in bits per pixel -- which means the number of digital ones and zeros the scanner uses to record color information about each dot. A 24-bit scanner can record up to 16.7 million different colors, about as many as your eye can discern. You'll find 30-bit scanners on the shelves, but it takes a graphics pro to take advantage of the quality.

Make sure you get a scanner that's "Twain compatible," which means it meets industry standards and can be controlled directly by many graphics programs.

This can save a lot of time by eliminating "middleman" software that does nothing but operate the scanner.

Finally, look at the software that comes bundled with your scanner. Better units usually include a capable image-editing program as well as the "lite" version of a major publisher's Optical Character Recognition software.

Pub Date: 11/24/96

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