Finding the right scanner can be a challenge. Most can scan just about anything, but these devices come in a variety of types and sizes that are fine-tuned for different purposes. Here are the key questions to ask to help make sure you pick the right scanner – or scanners – for your needs.
What do you need to scan?
Knowing what you expect to scan and how often you expect to scan it will tell you everything you need to know about the features you'll need. The two most common choices are photos and documents (as unbound pages), but there are other possibilities too – books, business cards, film (slides and negatives), magazines, and easily damaged originals like stamps are all reasonably common. Somewhat less common are 3D objects like coins or flowers. Also, consider details like the maximum size of the originals and whether you'll need to scan both sides of document pages.
Do you need a flatbed?
For photos or other easily damaged originals, bound material, and 3D objects, you need a flatbed. (Here we're talking about scanning 3D objects to two-dimensional images; 3D scanners – for scanning objects to 3D files for display or printing – are a different beast entirely. 3D scanners are still in their infancy, but we expect them to be of growing importance in the coming years). Originals like photos and stamps can go through a sheet feeder, but you risk damaging them. If you need to scan this sort of original only rarely, you may be able to make do with a sheet-fed scanner that comes with a plastic carrier to protect the originals. Bear in mind, however, that even brand new, unscratched plastic carriers can degrade scan quality.
Do you need a sheet feeder?
If you plan to scan documents on a regular basis – particularly documents longer than one or two pages – you almost certainly want a sheet feeder. Having to open a flatbed lid and set a page in place is a minor chore. Having to repeat the process 10 times for a 10-page document is a tiresome annoyance. Some sheet-fed scanners can also handle thick originals, like ID cards for example.
Do you need an automatic document feeder?
If you'll primarily be scanning one or two pages at a time, a manual sheet feeder is probably all you need. If you'll be scanning longer documents on a regular basis, however, you'll want an automatic document feeder (ADF) that will scan an entire stack of pages while you do something else. Pick an ADF capacity based on the number of pages in the typical document you expect to scan. If you occasionally have a longer document, you can add pages during the scan. Some ADFs can also handle stacks of business cards well.
Do you need to duplex?
Duplexing means scanning both sides of a page at once. If you need a sheet feeder or ADF, and if you expect to scan duplex documents (printed on both sides) on a regular basis, you'll want a duplexing scanner, duplexing ADF, or a scanner with a driver that includes a manual duplex feature.
Duplexing scanners have two scan elements, so they can scan both sides of the page at once. They're faster than duplexing ADFs, but they also cost more. Duplexing ADFs scan one side, turn the page over, and then scan the other. Drivers with manual duplexing let you scan one side of a stack and then manually re-feed the stack to scan the other side, with the scanner driver automatically interfiling the pages. If you don't scan duplex documents very often, or are on a tight budget, manual duplexing in the driver is the most economical alternative.
What resolution do you need?
For most scanning, resolution isn't an issue. For documents, even a 200 pixel-per-inch (ppi) scan will give you good enough quality for most purposes, 300 ppi is almost always sufficient, and it's hard to find a scanner today with less than 600 ppi. For photos, similarly, unless you plan to crop and focus in on a small part of the photo or print the photo at a larger size than the original, 600 ppi is more than enough.
Some kinds of originals, however, require higher resolution. If you're scanning 35mm slides or negatives, for example, you'll probably want to print them at a much larger size than the original, which means you'll need to scan them at a high resolution. Similarly, if you want to see the fine detail on an original like a stamp, you'll need to scan it at a high resolution.
In these cases you'll want at least a 4,800 ppi optical resolution. Don't be confused by high numbers for mechanical or interpolated resolution – both are irrelevant. Also note that the actual resolution is usually lower than the claimed resolution, because the actual resolution is usually limited by the quality of the optics in the scanner. However, it's generally a safe bet that the higher the claimed resolution is, the higher the actual resolution will be.
How large are your originals?
Picking a scanner that can handle the size of the originals you need to scan seems like an obvious point, but it's easy to overlook. For example, most flatbeds are A4 size, which will be a problem if you occasionally need to scan slightly larger-sized pages – you can find scanners with larger flatbeds if you need one.
What software comes with the scanner?
Most scanners will work with just about any scan-related program, but if the software you need already comes with the scanner, you won't have to pay extra for it. Depending on what you plan to scan, some of the software features you may want to look for include photo editing, optical character recognition (OCR), text indexing, the ability to create searchable PDF documents, and a business card program.
Do you need a special-purpose scanner?
Finally, consider whether you need a special-purpose, rather than a general-purpose, scanner. Among the most common special-purpose choices are scanners for business cards (small and highly portable), books (designed to let pages lie flat), and slides (smaller than flatbed scanners, but no better at scanning slides than flatbed scanners with equivalent features).
Two other possibilities are portable scanners (general-purpose sheet-fed scanners small enough to fit in your laptop bag) and pen scanners (the size of a pen). Some of the latest portable scanners can operate without a computer, scanning to a memory card, or even to a smartphone. You can also find scanners that function as both portable and desktop document scanners by combining a portable scanner with a docking station that includes an ADF. Depending on what you need to scan, any one of these may be a good choice, either as your only scanner or as a supplement to a general-purpose scanner.
While you're here, you might also want to check out our 12 handy tips on scanning all those family pictures.