Go to the heart of the image

Do you want to stock your invoices and contracts permanently? Or do you wish to prolong the lifespan of a picture, or even edit it with special software? You will need a scanner in all these cases. With this device, you can digitalize all your documents, that is, transform them in digital data. This allows you to archive them on your computer and re-use them later. Here, you will find some tips to find the scanner that meets your requirements.

Use

Do you want to stock your invoices and contracts permanently? Or do you wish to prolong the lifespan of a picture, or even edit it with special software? You will need a scanner in all these cases. With this device, you can digitalize all your documents, that is, transform them in digital data. This allows you to archive them on your computer and re-use them later. Here, you will find some tips to find the scanner that meets your requirements.

All the scanners function in the same way:

In order to make your choice between the different types of scanners, you need to figure out for which activities you will use the scanner daily, and what type of documents you will need to digitalize.

Flatbed scanner

This is the most common model among the scanners. In order to scan a document, it must be put flat on the glass.
The quality of the end result depends certainly on the quality of the scanner. The high-end scanners offer here the best resolution.
Thanks to the function for the removal of dust and scratches, you can restore easily and fast the image of old pictures with a damaged surface.
You can even digitalize with some scanners your slides and negatives, with the aid of a backlit adapter, especially designed for this task.

Mobile scanner

When you are often on the road and you need to scan mostly sheets with text (PDF, Word, Excel, Powerpoint…), it is recommended to choose for ultra-portable models, that are light and fast. You just need to pay attention to the connectivity of the product.
Among the mobile scanners, the Bluetooth models are the most “free”, as they don’t need any cables: the scanned data are registered on the memory card of your scanner, and exported next to your computer thanks to the wireless connection.

File or document scanner

When the scanner needs to be used for archiving documents (e.g. invoices) , a document scanner is indispensable. This type of scanner has always a document feeder. It can scan a complete pile of paper without any human intervention, which makes it possible to save a lot of time!

Business card scanners

If you only need to scan business cards, there exist very compact devices with special integrated software, that make your life more easy.

GOOD TO KNOW : in order to save or to share your favorite articles, it is advised to use a book scanner. With this type of scanner, you slide manually the scanner over the page, for digitalizing it automatically. If you wish to buy a book scanner, please contact us.

USEFUL TIP:

Before you buy a scanner, don’t forget to check if the operating system is compatible with the system of your computer!

Quality of the scan

The quality of the scanned image depends on three criteria: the resolution of the scanners, the sensors and the color depth.

The resolution

The resolution corresponds with the number of points (or pixels) detected by the scanner on a given surface. This is expressed in dpi (dots per inch). The higher the resolution, the more the detected pixels will be small and numerous, and the more the image will be accurate.

At the choice of the device, it is necessary to check the optical resolution, as this really determines the accuracy of the detection. However, few attention need to be paid to the interpolated resolution: this only corresponds with the capacity of the scanner to determine the color of the pixels of unknown colors, with the assistance of the colors of neighboring pixels.

   

Intended use of the scanned images

Advised resolution

Editing or printing

300 dpi

Enlarging

500 dpi

Processing with character recognition software

150 dpi

Publishing on the internet

72 dpi

The sensors

The presence of visible pixels is called “noise” or “grain”. This phenomenon reduces the quality of the image.

In order to obtain an image with as less “grain” as possible, you need to choose for a scanner with a CCD sensor (charge-coupled devices): they are equipped with a cold lamp, type neon, that produces a very weak signal/grain ratio.

The scanners with CIS technology (contact image sensor) integrate CMOS sensors (complementary metal oxide semi-conductor), that react to the illumination with LED lamps. They are very interesting, as they are more energy-saving. At the same time, they are more compact, so they occupy less space.

The color depth

The color depth measures the capacity of the scanner to distinguish color shades. It is expressed in bits, and the higher the number of bits, the more optimal the display of the colors will be.

A scanner of :

GOOD TO KNOW : at the purchase of a scanner, you must check first the color depth of the input and the output. They correspond respectively with the internal color palette of the scanner and with the image that is send from the scanner to the computer. For an optimal return, it is important that both figures are the same.

Scanning speed

The scanning speed is expressed in s/page (= number of seconds that is necessary to digitalize 1 page) or in ppm (= number of scanned pages in 1 minute).
Try not to mix these values: if you want to have a fast scanner, the number of s/page needs to be low, and the number of ppm needs to be high!
In order to be clear, we indicate systematically these two values on our product sheets.

GOOD TO KNOW :the illumination influences the quality and the speed of the scan, especially for slides.

There are three types of lamps:

Some specialized devices are equipped with an extra lamp, in order to remove dust and to clean up the image with special software.

Interface and software

All electronical devices, scanners included, are equipped with an interface, in order to connect them physically to other devices. The parallel port is not used a lot any longer. It is now repressed by the USB stick (Universal Serial Bus) 1.1 and 2.0, and theFireWire. This last one has a much larger scanning speed.

If you want to connect a scanner to a computer, the respective interfaces (parallel port, USB 1.1 and 2.0, Firewire…) need to be compatible, or it will be necessary to buy an adapter. Luckily, most recent scanners have several interfaces, which increases their compatibility.

The TWAIN driver, protocol for communication between a computer and a scanner, has often a depixelating function, which is practical for scanning printed documents. Most scanners are furthermore delivered with software to edit pictures (Adobe Photoshop) or to recognize characters of a text (OCR).

Finally, some scanners have drivers, in order to use them in a network. In that case, one single device will be shared by several users, so you can save space and money!

Terminology

Bluetooth : universal norm for wireless connection to exchange data between mobile devices and/or to other compatible equipment.

Sensor : electronical component that reacts to the light. It integrates a large number of photosites, indicated in general with pixels, that accumulate electronic loads, stimulated by the light. The electronic loads are send next to an electronic circuit, that can transfer signals into digital data. There are two types of sensors: the CCD and the CMOS.

CCD sensor : charge-coupled devices. The electrical signal is transferred from pixel to pixel by light stimulation, originating from a neon lamp. This causes an especially low signal/noise ratio, and results in a clear image.

CMOS sensor : complementary metal oxide semi-conductor. The pixels react by light stimulation, originating from LED lamps. These LED lamps require less energy and the scanner fits in a more compact body.

Feeder : the feeder allows you to load a series of sheets in the scanner, without needing to open the lid. Some feeders are even equipped with a function for double-sided scanning, which increases their activity.

CIS : contact image sensor. Technology on scanners that are equipped with CMOS sensors.

Depixelating : software function installed on the drivers of most scanners, in order to remove the frame on scans of printed documents with a grid, e.g. newspapers, art magazines and journals.

OCR : optical character recognition. Scanners equipped with OCR software are able to transfer scanned documents, PDF files and digital pictures to searchable and editable documents. This technology avoids that the scanned information needs to be rewritten, and it gives you the possibility to work with search terms in a scanned text.

Resolution : the optical resolution corresponds with the total number of pixels that the scanner detects on a surface of 1 inch (1 inch = 2,54 cm). It is expressed in dpi (dots per inch) and allows you to indicate the quality of the image definition.

DPI : a unit of measurement for the number of pixels, recognizable for a length of 1 inch.

TWAIN : this is a protocol for communication between a computer and a scanner. It eliminates most of the problems with the compatibility of the software on devices from different manufacturers.