Despite the fact that scanners are very familiar to us, we might not know what they are all capable of. All too often, we just assume that these things work and use them whenever we want, but you want to know exactly what goes into a scanner in order to find the best scanner for your needs.
Here are some of the key features of a scanner to consider before you buy.
Main Features of a Scanner
The Feeder Type
To begin with, you want to find out what kind of scanner you want which breaks down to two main categories: flatbed and sheetfed. A flatbed scanner will just offer a flat surface upon which you place the document for scanning, close the lid, and hit the scan functions. A sheetfed scanner utilizes a feeder port will bring documents into the scanner in order to be scanned.
The best scanners as far as resolution are usually flatbed scanners. Photo scanners are usually flatbed for optimum image resolution. However, for those of you just scanning documents, sheetfed scanners can often work more quickly making them the better choice for bulk document scanning.
Compatibility of the Software
You also have to consider the software that you need in order to run the scanner, and if you can get it to work with the kind of computer you have. Make sure you look at the drivers that device needs specifically to work; they can often come with the scanner, but you might have to update them from time to time in order to get them to work. And always make sure a scanner with work with your operating system, be it a PC or a Mac.
Color Depth and Resolution
In the event you are concerned about how good the image looks in the scanner, take a look at the resolution and color depth that is offered with that scanner. The DPI, or dots per inch, is what determines the resolution; the higher the DPI, the better the image will turn out all things being equal. When looking at color depth, you are finding out the amount of color that every pixel can receive; the higher the depth, the better the quality of the image. These criteria are especially important when comparing the photo scanners where the image quality is critical.
Scanning Bed Size
You will find many flatbed scanners to hold anything of legal paper or smaller size (8.5″ x 14″). For those people who want to scan bigger images than that, you will either need a large flatbed scanner or utilize a software stitching program for piecing together multiple small scans of a large item. There are actually large format scanners that will scan up to an 11×17″ size.
A lot of scanners are an all-in-one package, usually referred to as all-in-one printers. An all-in-one printers will scan, print, and even fax a document while maintaining the size of a standard printer. Those who have home offices in which scanning is just one need will be well served by a multifunctional device. You can cut down on costs by only purchasing one machine that does all of that, plus save space in your office. On the flip side though, you will likely lose a bit in image quality.
Warranty and Service
You can often run into issues when running technical equipment such as this. Therefore, you really want to take a look at the service plan and warranty that you have with it. Verify that you do not have to pay anything to send it in for repairs in the event that something goes wrong with it, especially within the warranty period. Also check for a dedicated customer service line should you need help with troubleshooting.
Even though you might not realize it, it is important to recognize the price of your scanner before you buy it. If all of the scanners you are looking at have the same features and are interchangeable to you, use the lowest price to decide. If your scanning will only be done occasionally then you may be able to get away with buying a cheap scanner.
Guide to Scanner Specifications
The first step in making a good purchasing decision on anything is to understand the specifications of the product and what they mean. Reading that a scanner has a 4800 dpi is basically meaningless to you if you have no idea what dpi is.
You don’t have to be a total technological guru to decipher the basics of scanner specifications, however. Take a few moments to review the basic definitions and you’ll be armed with all of the knowledge you need to find the best scanner for your situation.
The term resolution refers to nothing more than the quality a scanner is able to produce based on how many pixels it is able to sample. Resolution takes place on a grid, and the number used for dpi (dots per inch) refers to how many squares are contained within that grid.
Most common flatbed scanners have a resolution of at least 1200 dpi. Remember that no matter how many times the scanner head is programmed to stop, the resolution will never be more than how many sensors are contained in the head, so the lowest number is all that matters. A 1200 X 2400 dpi scanner will still only produce a 1200 dpi image.
Bit-depth is simply the amount of information a scanner is capable of recording for every pixel it looks at and is responsible for the colors a scan can produce. Low bit scanners can only see black and white and generally produce low quality scans. Most color scanners today operate at 48 bits, although some manufacturers are still making lower bits of 24 and 36 available.
There are some compatibility issues with these very high bit depths, however, as most personal PCs are not able to handle the amount of information. 24 bit is very close to photo quality and is sufficient for the purposes of most but most of the newer flatbed scanners seem to come with 48 bit.
Dynamic range is similar to bit-depth, but focuses on the range of colors a scanner is capable of capturing. Higher dynamic ranges mean truer colors. It is measured from perfect white to perfect black, 0.0 to 4.0 respectively. Most flatbeds offer 2.4, which is good enough for most personal projects, but does not produce high photo quality. For that, you will need 3.2 or higher.
There are two types of scanning methods that are used: the charge-coupled devices, or CCDs, and contact image sensors, or CIS. CCSs produce higher quality images because they use an intricate sensor, light, photo cells, and mirror approach to capture the image to be scanned. They are generally what would be found in a traditional flatbed scanner. CIS, on the other hand, use only light and a single row of sensors in very close proximity to the document, creating an ultra thin scanner, but one that does not produce as high quality of an image.
The scanning area quite simply refers to the document size a scanner is able to accommodate. Sheetfed scanners can generally handle any sized document while flatbed scanners are limited to their size. Most will only accommodate standard letter sized paper, but large flatbed scanners will be able to scan letter-sized documents as well as 11 x 17 inch documents.
Short of taking a scanner for a test run, it can be difficult to determine the speed since there is no established standard. Generally speaking, however, higher quality resolutions will require longer scanning times than low resolution scans. Scanning software usually allows you to choose the resolution you wish to scan at, so for non-images you can go faster by choosing a lower resolution.
Speed may be more important to you if you have the need to scan many items a day. Document scanners are usually the fastest at scanning because of their auto-feeding features. Scanning with a flatbed scanner will always take longer.
The Bottom Line
You should not make the mistake of focusing in on any one of these specifications in scanners to determine the overall quality of a device. Each of them is important for determining the ultimate quality of an image. A high resolution with a low dynamic range may produce excellent quality document scans, but will disappoint you if you are looking to scan photos. Consider what your needs are and focus on getting the highest specs that are vital to that purpose.
While this isn’t a comprehensive list of all of the key features of a scanner the list here contains some of the more important elements. When trying to determine the right choice for your situation, it is important to understand that no scanner is perfect. Weigh your needs against the available features and specs of a given scanner and let the best scanner win.