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What Scanner Features Do You Need? 157
Flatbed scanners have a fixed-size scanning bed, usually 8.5 x 11.7 to 8.5 x 14. Even though you might rarely scan a 14-inch-long original, the larger size is handy to have. I often slap down a bunch of 4 x 6 prints and scan them all at once, cropping and sizing within Photoshop. Itís nice to have a larger scanning bed to accommodate more and larger originals when you need to.
If you have many color slides or negatives youíd like to scan and donít want a dedicated film scanner, a flatbed that can accommodate these originals is a plus. A light source built into the lid of the scanner can transilluminate the film so the sensor can capture your slides, negatives, or transparencies, using the scannerís highest optical resolution. Figure 4-4 shows such a scanner.
Figure 4-4: A flatbed scanner with a light source in its lid can scan film.
If your desktop space is limited, you might want a tiny scanner. I favor larger scanners because they tend to stay put without sliding and can better ignore
Adding a Printer and Scanner
158 What Scanner Features Do You Need?
vibrations when heavy-footed colleagues or family members stride past. In any case, even the largest flatbed scanners today are likely to be half to two-thirds the size of the behemoths of ten years ago, so you wonít have to worry about giving over half your desktop to your image grabber.
Along with physical size, other scanner configuration features can be important when desktop space is limited. For example, a few scanners can be set up vertically so they occupy a minimum amount of space. At least one new scanner comes apart, so you can place the scanning element directly on a large original that wouldnít fit in an ordinary scannerís scanning bed. The scanner in Figure 4-5 lets you see the original being scanned through a transparent lid.
Figure 4-5: Some scanners let you see the subject you are scanning through a glass sheet.
If youíre already well equipped with software, you probably donít need to worry about the bundle furnished with your scanner. I have several copies of Adobe Photoshop Elements that came with scanners, but rarely use any of them. Of more interest to me are the advanced scanning programs, such as the versatile Silver Fast application that came with my high-end Epson scanner. You can always upgrade to better software if youíre dissatisfied with the applications furnished with your scanner.
What Scanner Features Do You Need? 159
You might be more interested in OCR software (to convert documents to editable text), copy utilities (to let you use your scanner as a photocopier), document management programs (to let you file document images and retrieve them by keywords), and other software, such as applications that let you stitch images together to create panoramas.
Type of sensor
The kind of sensor used in a scanner can affect how you use it. In the past, charge coupled device (CCD) sensors were the most common sensors in consumer scanners. These solid-state devices capture an image that is conveyed by a sophisticated optical system, often a path measuring a foot or more in length, as mirrors and optics convey the light reflected from the original to the sensor itself.
More recently, a less expensive, solid-state sensor called a contact image sensor (CIS) has been used, especially for lower-priced scanners. A CIS sensor moves beneath the glass a few scant millimeters from the original in a much-simplified system that requires no optical path at all. CIS scanners can be very thin and compact (because there is no need to leave room for an optical path) and use inexpensive red, green, and blue (RGB) light-emitting diodes (LEDs) instead of the fluorescent light tube found in CCD scanners. This makes for a cheaper scanner, in more ways than one:
? CIS scanners often produce poorer quality than the more sophisticated CCD sensor produces. Although quality is improving (some $150-$200 CIS scanners produce great quality), this technology has not been associated with the best overall quality.
? CIS scanners typically have very little depth of field, which means they can scan only flat originals held in tight contact with the scanning glass. Even a wrinkle in a paper original can affect the sharpness of some CIS scanners. You can also forget about scanning 3-D objects.
Until CIS sensors catch up with their CCD counterparts, you probably want to stick with a CCD-based scanner when making your decision. Check the box or specs to find out which you have or visit the vendorís Web site if the information isnít easy to find.
The kind of interface used to connect your scanner to your computer was once an important consideration. You had to choose between SCSI or parallel port scanners or even slow serial connections. Some scanners required a proprietary interface card.
Today, all scanners come with Universal Serial Bus (USB) or IEEE 1394 (FireWire) connections or both. Either of these interfaces is fast enough for