How To Buy A Scanner
Scanners can be used for multiple purposes, from creating digital images from your old photos to transferring important papers to digital files. Before you rush out and buy a new scanner you need to be aware of your intended use for it, to ensure you get the best model for your requirements.
There are various types of scanners, but the most common and versatile scanner is the flatbed. It operates very much like a copy machine. The image you want to scan is placed on a glass plate under the top cover. Flatbed scanners can normally scan photo negatives as well as original photos and documents.
You can also buy sheet-fed scanners, in which you insert the document to be scanned much like a fax machine. The disadvantage is that the document has to travel through the machine to be scanned, which can cause damage to your precious photos if something goes wrong.
If your main purpose is to scan a large volume of documents then the document feeder scanner is perhaps the best choice. This type of scanner enables you to feed the documents through the machine by placing them in a document tray, similar to a printer. They are fed through the scanner automatically at rates of between 20 to 150 pages per minute.
The duplex scanner is more complex. It operates in the same way as a document scanner, but has the capability to scan both sides of the document automatically.
All scanners come with the necessary software to connect, capture and store the image on your home computer. But often you will want to do more than just that with your stored files. Many scanners come with some form of image enhancing software, for example to remove "red eye" from scanned photos, or to adjust the brightness or contrast. More complicated software is often available that includes optical character recognition (OCR) to enable you to search through your scanned document images.
Possibly the most important specification for a scanner is the resolution, usually given in pixels per inch (ppi). A modern flatbed scanner can reach up to 5,400 ppi resolution. Sometimes scanner manufacturers will claim interpolated resolution, which relies on software to manipulate, or interpolate, the image, but this can be misleading as it does not actually increase the level of detail captured. Remember though that the higher the resolution, the larger the scanned image will be and doubling the resolution will quadruple the file size.
So remember to choose your scanner according to your needs, a high resolution, flat bed scanner for photos or a lower resolution document scanner for large volumes of documents.