Scanner Guide
Need to convert a photograph or hard-copy document into digital form so that you can edit or email it? A scanner can do that! They're handy and a lot of fun for home projects, but let's consider a few things before you make your decision on which scanner to buy.
Since most scanners tend to be inexpensive, they have a fairly low profit margin for the manufactures. Instead of upgrading the core hardware, manufacturers are now making scanners more user friendly in an effort to boost sales. HP for example, has added a photo feeder tray to some models, and Epson is incorporating its Print Image Matching technology into newer units, to simplify the colour calibration between the scanner, your system, and Epson printers, giving more life-like resolution when you print the scanned document.
Scanner basics
Optical resolution Today's consumer scanners usually offer optical resolutions of up to 2400 dots per inch. If you're going to be displaying snapshot sized photos on the Web or printing them out, 100 dots per inch is plenty of resolution, for capturing text using optical character recognition, 300 dpi is standard; and any inexpensive scanner on the market will do. But if you want to make 8-by-10-inch or larger photo prints, or enlarge smaller images, you'll want a scanner with 1200 dpi or 2400 dpi of optical resolution. You'll have more flexibility in editing your image if you start with the highest possible resolution. But remember, high-resolution images take up a lot of hard disk space, for example, a 1200-dpi, 4-by-6-inch photo can consume as much as 25MB of hard-drive space.
Automatic document feeder For scanning pages that are longer than a flatbed's scanning surface, an automatic document feeder can be very helpful. ADFs are typically built into, or can replace the scanner's lid.
colour depth The amount of colour (and gray-scale) data that a scanner can recognize and save, termed colour depth, is measured in bits per pixel. A scanner can usually capture more data than its driver can save, so you'll usually find a notation on the scanner's specs, such as 48-bit internal or hardware colour. This describes how much data the scanner can recognize. External or true colour tells you how much data the scanner's driver can save. For most general-purpose use, 24-bit external colour depth will be sufficient.
Sensor technology Flatbed scanners use one of two types of sensor technology: a charge-coupled device (CCD) or a contact image sensor (CIS). CCDs, use an older technology, but offer superior scan quality. CIS-based scanners are usually much smaller and use far less power than CCD-based scanners.
Scanner type Most scanners on the market today are called flatbed scanners, because their scanning surface is flat. On a flatbed scanner, you simply open the lid and place the object you want scanned onto the glass panel, just like a copying machine.
You'll also find sheet-fed scanners, handheld scanners, photo scanners, and multifunction units that incorporate a printer, scanner, and fax machine into one device. Choose the one that best fits your usage needs.
Software All scanners come bundled with the software necessary to direct the scanner to read an object and transfer it to your PC. Most scanners also come with simple image-editing software so you can touch up colour imperfections and optimize the files for e-mailing or printing. Many high-end scanners also come with optical character recognition, or OCR, software that allows you to scan a printed document and convert it to text that you can edit on your PC.
Now that you understand the basics, here's some shopping tips:
For general use flatbeds are fine. These models are inexpensive, easy to use and versatile enough for most tasks.
Look for at least 1200-dpi optical resolution. Though such models cost a bit more, they are worth the investment. A scanner with this level of resolution and colour depth will allow you to print photos using state-of-the-art photo printers. The print quality is on par with most photo shops.
Look at your PC's USB port. Almost all modern scanners connect to your PC via a USB port. If your computer's less than two years old, it should have one. If you don't have a USB port, make sure to look for a scanner that will hook to your PC's parallel (or printer) port.
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