The term "scanner" means a few different things. It can mean an electronic device that "scans" the waves and searches for specific signals that the owner has requested it broadcast when anything is received. This is the type of scanner that is so often used by emergency services or law enforcement agencies, but which might also be a device used by the general public to keep up to speed on any radio activity in the range of the unit.

Scanner types

Then, there are the very common scanning devices used by millions of people seeking to transfer an image, document, or other media to their computer or memory device. These include:

Flatbed scanners

Similar in looks to a classic photocopier, the flatbed scanners are able to capture flat items such as pages or pictures, but can also copy books or even paintings and three-dimensional objects when the items are placed on the platen glass. A scanning head passes beneath the item and converts it into a workable computer file. Some scanners have software that may even convert an image file to a working word processing file.

Slide or film scanners

Also capable of capturing images from transparencies, these can be similar in design to flatbed models, but usually have some sort of frame or adapter into which the film, negatives, or transparencies are placed for scanning.

Handheld scanners

Looking like a wand or even a computer battery, the handheld scanner is meant to slide over the document rather than the traditional scanning of the document while in a fixed frame. These usually preserve the image file on a memory card or device, and it is this that conveys the details to a computer.

Portable scanners

Also known as "sheetfed" scanners, these are units that can be easily carried in a bag or briefcase and which scan a document by sliding the page through and across the scanning head. Because of their design, however, they do not usually have the same capabilities as the full-sized flatbed scanners.

What to Know

Once you understand the type of scanner you need, it is important to determine if it has the capability and quality you require. This begins by understanding how the device actually views the material it will capture. For instance, the scanners always have sensors, and you will want to know the difference between a CCD and a CIS scanner.

Most flatbed scanners utilize the CCD, or charge-coupled device that illuminates the item being scanned and then relies on a series of mirrors and lenses to capture it in the highest quality possible.

You also want to understand the "bit depth" of your scanner. If you are going to just scan documents containing text, and you are not worried about the colours or the actual quality of the end results, you can get by with 24 bit depth. However, most people using scanners need a higher quality result, and that means that 30 to 36 bit depth is recommended.

Just like photographs need good resolution, so too do scanners. Because most scanners are using optical devices to capture their data, it means that the buyer must find out how many "dpi" or dots per inch (this may also be called the "ppi" or pixels per inch) the scanner will capture.

Because many scanners have dual functions (capturing text when needed or high-quality images too), you will want to seek out units that have at least 300 dpi for text and at least 600 dpi for photos. You also need to note that any slide or negative scanners should provide the highest quality possible, with at least 1200 dpi available.

Connectivity and Software

Another major point to consider when seeking out a scanner is how it will connect to your computer. While most use USB ports and "FireWire" ports, some have wireless options too. Just always keep in mind that the higher the quality of the scan, such as a 1200 dpi scan, the longer it takes to do the work. The scan will take a while, and the loading of the file to the computer will take some time too. The best systems offer USB 2.0 connections, but a FireWire works well too. 

Many good scanners come with essential operating software. This means that you may get a handy photo editing program with a scanner, OCR or optical character recognition software that converts scanned text to workable text, and image management software that creates folders and manages all of the materials scanned.

Pricing

In the end, you will find that you will not have an endless array of models from which to choose, but you do want to invest in the best unit possible. Compare the prices of the different scanners that offer the features you need, and you should be able to find one that delivers the files you require for work, home, or even for your artwork.