A scanner is a peripheral device that is connected to a computer to convert written documents into digital form. Digitized documents can be edited or stored in a computer for future purpose. Scanners come in different types. Some devices are capable of digitizing any documents, while some are capable of supporting only certain types of documents.

When you plan to buy a scanner of your own, there needs a careful scrutiny about the type of scanner that are available in the market. This is essential to see if it suits your requirement.

How to decide upon a scanner?

Buying a product of our own is not important. But buying a right product that is suitable for our use is more important than any factor. It gives immense pleasure to the user when he discovers that the product is completely satisfactory. It is also worth buying such a product.

Selecting a scanner must always depend upon the type of user. Users are of different types. They are beginners, intermediates and advanced.

Beginners

If you intend to use your scanner for simple use such as filing of documents, then a flat scanner that has an optical resolution of 600dpi or less than this will be the apt choice. You can also opt for sheet fed scanner depending upon the document type.

Intermediate

If you intend to digitize documents and photographs in great aspect, then you can very well go for any model in flat scanners, which have a 24-bit depth sampling.

Advanced

If you have to digitize negatives or quite large documents, then you can go for an advanced model with the feature of scanning transparencies or models that come with image editing software for professionals.

Types of scanners:

Flat scanner

Flat scanner is a commonly used device. All forms of documents can be scanned, especially A4 size documents. A3 scanners are also available. Documents can be scanned by placing it against the scanner’s screen. Flat scanners are also capable of scanning documents on negatives or transparencies.

Film scanner

This type of scanners can be used by professionals. It is specialized in digitization of 24 x 36 negatives. Scanned documents have excellent quality and high resolution.

Rotary or drum scanners

In this type of scanner, image is passed several times across the photomultiplier drum to get clear image. This type of scanners is used by the professionals.

Sheetfed scanner

This type of scanner has the feature of digitizing sheet per sheet. You can feed in the paper through the feeder or through an opening and the document appears on the computer screen. This scanner is very compact and has limited usability.

Factors affecting the performance of the scanners are:

Scanner type

Before deciding upon any scanner you must decide on the type of document you will be scanning.

Colour sampling depth

A scanner with 10 bits can make a distinction of 1024 colours. A scanner with 24 bits make a distinction of 16.7 million colours and a scanner with 48 bits can make a distinction of 480 billion colours. The more the number of bits the better the colour gradation will be.

Optical resolution

Dot per inch (dpi) or points per inch (ppi) are the number of dots or points that are made in one inch. It is better to go for a scanner with 600 x 600 ppi.

Interfaces

Interfaces are also a major factor to be considered while buying a scanner. Proper port must be used in the scanner.

USB port

USB ports are widely used than the parallel ports. USB ports offer better performance and a reduced usage of processor’s resources. It is compatible to both Mac and PC. Some scanners can be directly connected with the USB port.

SCSI (Small Computer System Device)

SCSI (Small Computer System Device) has the lowest processor resources consumption and is widely used for professional work.

The software

The software in the scanner is classified into image editing and character recognition.

Image edition

Image editing is always suitable for small editions than the advanced types. Commercial software cost more than the lighter versions.

Character recognition

This software can read a text image and convert it to a text document. The major advantage of the scanner is OCR (Optical Character Recognition).

General

Scanners that are available today are quite slim and built with buttons for automatic function. The overall appearance of the scanner may depend upon the features available in it. Scanners are more affordable in recent days and are also a useful medium to store and edit documents. The software you install must function well during the post-scanning operation too.