A scanner is a device that uses light-sensing equipment to import documents into programs to be edited and saved. They can be used to convert photographs into computer images or printed text into an editable text document. While not a very common component, scanners are used heavily by professionals such as publishers and photographers.

You should consider getting a scanner only if you would use it regularly. For most people, the occasional convenience that scanners provide is not worth their cost. There are alternatives to the functions scanners provide that are much cheaper, if less convenient. If you need a text document converted to a computer document file, you can usually have your local print shop scan it for you for a small fee. And most photo-development shops will put a roll of film on a Photo CD for a nominal cost. However, the purchase of a scanner is becoming increasingly justifiable as scanners fall in price.

Scanners range widely in sophistication, hardware interface, and design. The two most important attributes to consider in terms of sophistication are resolution (in dots per inch, dpi) and color depth (in bits). The resolution gives an idea of how fine an image the scanner can produce; if the scanner can differentiate more dots in a single square inch, images produced will look less blocky or pixilated and more life-like. The color depth gives an idea of how precisely the colors in images produced will mirror the ones they represent in original documents. If the number is greater (36-bit compared to 30-bit), the scanner theoretically has a larger palette of colors to work with. However, you likely would not notice any great difference between 24-bit color and 30-bit color; the difference is very subtle, and you will not see it at all if your display is set to a lower color depth or you save an image with a lower-quality file type. Usually, color depth is not a feature upon which you should base your buying decision or for which you should pay more money.
The three main scanner designs are flatbed, sheet-fed, and handheld. A flatbed scanner has a fixed glass surface upon which documents are placed to be scanned. Flatbeds are the bulkiest and most space-consuming type, but they allow bound documents to be scanned, and pose no risk to documents getting damaged. Sheet-fed scanners, on the other hand, which use wheels or rollers to move a document through them, are very compact, but are too small for most bound documents and can sometimes scratch photos or tear paper. Hand held scanners, which require the user to move the scanner over the document in a relatively smooth and even motion, are compact and will work with any type of document without any damage, but are apt to produce skewed or incomplete images.
All scanners use one of three hardware interfaces to connect to the computer: SCSI, parallel port, or USB. Parallel port scanners are usually the easiest to install, because they attach directly to the computer's printer port and require no special hardware setup. SCSI scanners, the installation of which is discussed here, have the advantage that they can transfer images more quickly to the computer. However, they require that a SCSI controller, a relatively uncommon component, be installed inside the computer. A SCSI controller must be either included with the scanner or purchased separately, so SCSI scanners are usually more expensive than parallel port scanners. USB scanners are just as easy to install on a Windows 98 computer as parallel port scanners. However, because USB technology was very new at the time of this writing, it was too early to determine how USB scanners compare to SCSI and parallel port scanners in terms of cost and performance.

Scanners range in price from $100 to over $500. When buying a scanner, you can easily narrow your choices to a few models by deciding on a design, hardware interface, and degree of sophistication that fits your budget. Another factor to take into consideration is the software included with the scanner. Every scanner should have a driver that lets you control the operation of the scanner when you're importing a document, an image editing program, and an OCR program to convert acquired text to editable text. Before buying a scanner, make sure that you will have surface space available close enough to the computer that you can attach a cable. If you're going to buy a SCSI scanner and you do not already have a SCSI controller, make sure there is a free expansion slot available for the type of controller (either ISA or PCI) that you plan to use.

It takes about 1 hour to install a SCSI scanner. No tools are needed.

Click here for a list of links to SCSI scanner manufacturers.
 

the installation

1. Install the scanner driver that came with your scanner in accordance with the accompanying instructions.

2. Install the image-editing and OCR software that came with your scanner in accordance with the accompanying instructions. If you are prompted by the installation programs to select a scanner driver from a list, choose the one that you have just installed.

3. If you want to use your scanner along with other SCSI devices that are already installed, and there is a SCSI diagnostics program installed on your computer (such as Adaptec SCSI Interrogator), use the program to find out the SCSI IDs of your devices. Write down these IDs, because when you connect the scanner you will need to make sure that it has a different ID than each of your other devices.

4. Turn off the computer.

5. • If you want to use your scanner along with other SCSI devices, you will need to daisychain all of the devices together and attach one end of the chain to the computer. Please refer to step 6 of the SCSI controller installation instructions.

   • If the scanner is your only SCSI device, attach one end of a SCSI cable to the scanner and the other end to the external port of your SCSI controller on the back of the computer.

   

6. Your scanner may have a locking mechanism that has to be undone in order for the scanner to function. (Please check the instructions included with the scanner.) If this is the case, unlock the scanner now.

7. Turn on the scanner, and start up the computer. Windows should recognize the scanner and associate it with the driver that you have already installed.

8. Click on the Start button, move the cursor to Settings, and click on Control Panel. Double click on the System icon. Click on the Device Manager tab, then expand the Scanners category. There should now be an entry for your newly installed scanner. If there is no entry, or if the entry has a yellow circle with an exclamation mark next to it, your scanner is not configured properly or there is a hardware conflict of some sort. Consult the manual that came with your scanner and/or use the Windows Troubleshooting Guide to resolve the problem. To access the Troubleshooting Guide, click on the Start button, then click on Help. Troubleshooting should be listed in the table of contents.

9. If your scanner driver includes a testing program, use it to make sure that your scanner is functioning properly. The testing program will probably prompt you to place a document on the scanner bed; it will scan it in black and white and show you a thumbnail picture of the result. You will know that the scanner works properly if the image closely resembles your original document. If you do not have a testing program, try scanning a picture using your image-editing software or a text document using your OCR software. You may have to briefly set up these programs to use your scanner.