- 15 January, 2004 09:00
Before choosing a scannerBefore choosing a scanner
When making a scanner purchase decision, many business and home consumers feel that they come up against a wall of confusion built with contrasting claims, multiple acronyms and a product range that can span in price from tens of dollars to tens of thousands of dollars.
Scanners have been around for a long time, providing the perfect circumstances for confusion and the wrong purchase - especially for the first-time scanner buyer.
One solution is to simplify your approach to your purchase while arming yourself with must-know information. It is better initially to ignore the hype and marketing and concentrate on exactly what it is you would like to achieve with your scanner.
Some examples are:
- My business needs to enter 1000 paper-based purchase orders into the computerised accounting system on a weekly basis (we all wish)
- I want to scan in all my photos so I can store them on CD
- I need to scan images from fat books and magazines for my Web site
- I want to restore my grandparents' old and damaged photos (because you're nice)
- I want to store the family's old holiday film slides on CD
Do this before you even begin to look at the available products.
This will ensure that the item you purchase will fulfil its role as a scanning device and help to safeguard you from over or under purchasing.
Some background info to considerSome background info to consider
The type of scanner most commonly sold to both homes and businesses is referred to as an A4 flatbed scanner. There is a wide market for these scanners and, as such, there is a wide range of products available, priced from under $100 to many thousands of dollars. This said, the under-$1000 market is very popular in the home and small business environments and provides a diverse variety of scanner products to the Australian market from dozens of different vendors.
Apart from price, which is usually commensurate with the capabilities of the scanner and the bundled software that ships with it, what distinguishes one model from another is the actual configuration and capability of the scanner package.
For example, a scanner with a built-in document feeder will probably be more expensive than one without. Another example is a scanner that ships with full versions of the software, which is normally more expensive than scanners that ship with 'lite' or cut-down versions of known software.
Basics no one will be bothered to tell you about scanningBasics no one will be bothered to tell you about scanning
The overall task of scanning is accomplished via the use of a PC or Mac, a scanner and software. The object of scanning is to convert paper- or film-based pictures or words into digital files on your computer. The files then can be stored, manipulated or used to create another hard copy document.
In almost all cases, you must connect the scanner to a PC. How you do this will depend on the scanner. Most entry-level scanners will connect via USB although some connect via SCSI or FireWire; the latter is more expensive but provides much faster data transfer when scanning large files, while providing higher quality scans. Be sure your PC or Mac has the appropriate ports for the scanner you will purchase.
Two of the main reasons most people may use a scanner is to reproduce an image or document for printing, or to reproduce an image or document for display on a computer screen. The commonest print resolution is 300dpi, which even the cheapest printer these days will produce. For display on computer screens, 72dpi is the acknowledged norm. Almost all scanners on the market today will be able to meet these requirements.
Forewarned is forearmed - have your answers READY!Forewarned is forearmed - have your answers READY!
The best way to ensure that you buy the right scanner is to have more answers than questions.
Make a check list
Whether you are buying for the home or the business, the salesman will probably ask you at least some of the following questions - which you should have the answers for:
- What tasks do you need the scanner to perform?
- What type of computer do you use? (i.e., PC or Mac)
- What is the configuration of the computer to which the scanner will be attached? (i.e., CPU, RAM, hard disk, etc.)
- Which operating system do you use? (e.g., Windows XP, Mac OSX, Linux)
- Which types of documents or items do you wish to scan? (i.e., pictures, slides, transparencies, books, documents, forms)
- How many scans do you expect to do per week?
- Who will be using the scanner? (i.e., novice, professional, student)
Have some background information memorised or close to hand. The following part of the guide is a brief overview of commonly available scanner technologies, what they do, how they work, and their associated options and software.
Scanner technology - the need-to-know stuffScanner technology - the need-to-know stuff
CCD stands for Charge Coupled Device, which is a type of technology first used in imaging by astronomers and is also the mainstream technology used in today's digital cameras. The charge coupled device accepts light and converts it to electrical charges that are then stored and manipulated into digital images. It has had over 20 years of development and started becoming popular as mainstream scanner technology in the middle of the last decade. The net result was cheaper, lighter scanners than those previously available, although the scan quality was initially not as good as the incumbent CIS technology scanners (this is no longer the case).
Contact Image Sensor (CIS) technology used to be the mainstream technology for flatbed scanners. It is not as popular today as it once was. Scanners using a Contact Image Sensor are usually larger and heavier than those using CCD technology.
One of the most important yet overlooked aspects of a scanner, the TWAIN driver is the piece of software that allows the scanner to do its thing on your computer. Almost every scanner has a TWAIN driver (TWAIN stands for Toolkit Without An Interesting Name). The capabilities of your TWAIN driver will affect other software, be it third party or bundled with the scanner.
As it is almost impossible for you to test every single TWAIN driver available, your best recourse is to read as many scanner reviews as you can.
The driver is the first point of call for the information that comes from the scanner to your PC. It is the software that allows you to determine the basics such as which resolution you are scanning at and what type of image or document you are scanning. Effective TWAIN drivers will also work as mini image editing packages, allowing you to at least crop, rotate, shrink or enlarge an image. Some have additional features such as contrast, brightness, gamma correction and other filters.
The bottom line is that the more effective, diverse and user-friendly your TWAIN driver is, the less potent your image editing or OCR software spend needs to be. The other advantage is that the greater the depth of detail the TWAIN driver can offer, the less work will be required on the image when it is transferred to the image editing software. Your scanner may be perfect from a hardware point of view, but if it ships with a crappy TWAIN driver it can make the scanner a tedious device to use.
Optical Scan Resolution
Scan resolution is one of the differentiators you will encounter when checking out scanners. There are usually two figures quoted and the more important one is optical resolution. Optical resolution of an A4 scanner refers to the number of dots of information into which that the scanner can convert the image. Basically, the greater the optical resolution scan, the higher quality output image you will get. This is vital if you will be scanning images to be enlarged or if you scan a small image and you want to enlarge it so you can edit out flaws. So, the bottom line is that the higher the optical resolution, the better the scanner technology.
Entry-level scanners priced up to about $200 will provide optical resolutions of at least 600x1200 at 48-bit. As the price increases, so does the resolution. Do not be frightened by this because as little as a $300 to $400 outlay will buy you a scanner with optical resolutions of 2400x4800 at 48-bit.
Interpolated Scan Resolution
This a scan resolution that is always higher than the stated optical resolution and is achieved by the use of software. Interpolated Scan Resolution refers to the number of dots of information that the scanner can produce from an image by the use of clever mathematical software that takes the existing number of dots that the scanner is capable of via optical resolution and increasing it. So when the salesperson quotes you the resolution the scanner is capable of, be sure that they are not quoting the interpolated resolution.
A bit is the smallest piece of information that a computer will handle. Bit depth refers to the amount of information each pixel (dot) can carry - and all images are made up of pixels. It can become quite confusing to sort out the technical details of how it works, but there are some good maxims that you can adhere to without having to know exactly what they means.
- More bit depth translates into better output because more layers of information exist in the scan.
- More bit depth means larger file sizes. For example, if you scan a normal colour photograph at, say, 300dpi resolution, first at 24-bits and then at 48-bits of depth, the 48-bit scan will have a much larger file size even though the scan resolution is the same.
In summary, the things you need to remember about bit depth when buying a scanner is that the greater the bit depth, the better the quality of the scan and the larger the file sizes. For almost all types of general-purpose use, 24-bit external colour depth is sufficient.
Software with which scanners are commonly associatedSoftware with which scanners are commonly associated
Image Editing Software
This is the software used to manipulate colour, greyscale and line art pictures, which usually correspond with settings in the scanner's TWAIN driver.
Almost all scanners will ship with some type of image editing software, whether it be a cut-down version of a full product such as Adobe Photoshop or the full version itself.
Optical Character Recognition Software
This software is used to get text documents into a word processor without having to retype the document. Good OCR packages will be able to understand a variety of languages as well as have the ability to retain formatting. As with image editing software, most scanners will ship with either a full version of OCR software such as Omni Page or a cut-down version.
Unlike printing, there are no ongoing consumables costs involved in scanning. Your scanner's initial purchase cost plus the cost of any accessories and additional software will pretty much determine the bulk of your scanning costs.
Some hidden costs to look out for are hardware upgrades to your PC that may be needed to run the software for manipulating the images or documents you have scanned. Other costs include the purchase of optional accessories such as automatic document feeders or film holders.
Also keep in mind that an A4 or A3 flatbed scanner will require a substantial amount of desk space. Remember, too, that if you are planning to do a lot of scanning - especially of colour images at high resolutions using large bit depths - then you are going to use up a lot of hard disk storage space.
Scanning costsScanning costs
Your scanning costs will be determined by your initial knowledge of your exact requirements of the scanner and how your PC needs to be configured to accommodate them. All things considered, it can range from under $100 up to tens of thousands of dollars.
|Scanners: an overview|
|Feature||Low End||Mid-range||High End|
|Resolution||600 by 1200 dpi||1200 by 2400 to 2400 by 4800 dpi||2400 by 2400 to 2400 by 4800 dpi|
|An important consideration. The resolution indicates how detailed the digital image will be. The higher the numbers, the sharper the scans will be. This is especially important when making enlargements.|
|Scan area||8.5 by 11.7 inches||8.5 by 11.7 to 8.5 by 14 inches||8.5 by 11.7 to 8.5 by 14 inches|
|Somewhat important. While few home users will need to scan legal-size documents, business users may find the letter-size scan area of most scanners too small. A larger scan area also makes it easier to scan large books, maps, drawings, paintings, newspapers, and tabloids.|
|Scan head technology||CIS or CCD||CCD||CCD|
|Somewhat important. CCD (charge-coupled device) scanner heads are far more common than CIS (contact image sensor) models, and generally provide higher-resolution scans. CIS-based scanners are often smaller than CCD scanners and may not need a separate power cord, but some models will scan faster if you use an optional power cord instead of powering them from the PC's USB port. CIS scanners can't use transparencies or automatic document feeders.|
|Scanner ports||USB 1.1, parallel||USB 1.1, USB 2.0, parallel, IEEE 1394||USB 2.0, IEEE 1394, SCSI|
|Somewhat important. Your PC has to have a compatible port to connect with the scanner. Most scanners come with a USB 1.1 port, which is fast enough for small jobs. Some scanners offer dual interfaces--like USB and parallel--to allow them to work with older computers. Only the newest USB 2.0-capable PCs are able to reap the speed benefits of a USB 2.0-capable scanner.|