When multi-function printers (MFPs) first became popular, a lot of people predicted that standalone scanners would disappear. That hasn't happened, however, and it doesn't seem very likely. The simple truth is that most scanners do a better job of scanning than most MFPs. That's enough to keep the category alive and well.
There are several different ways to slice and dice scanners into groups. You can draw a distinction between sheetfed and flatbed scanners, for example, or between portable and desktop scanners. However, the most useful approach, and the one we design our tests around, is to divide scanners by the kind of task they're meant for: documents, photos, slides, business cards, and so on.
Evaluating More Than Hardware
Our tests look at the software that comes with a scanner, as well as the scanner itself. That's because software is a key factor in determining what any scanner can do.
If the driver includes features such as digital scratch removal and color restoration for faded photos, or the bundled programs include a photo editor or photo album, for example, the scanner is meant for photo scanning. If the driver options include the ability to automatically skip blank pages in a document or to drop out a background color to make text more legible, and the bundled programs offer optical character recognition (OCR), document management, and document indexing, the scanner is meant as a document scanner. If the software covers both areas, the scanner is meant for both. Some scanners also have specialized software for turning business cards into digital contacts or pulling financial data from receipts.
How well a scanner does at a given task depends on both the hardware and software. A given scanner may be capable of doing a good job of scanning business cards, for example, but if it comes with an inferior business-card program, its performance on our tests will reflect the limitations of the program, not the potential capabilities of the hardware should you choose to buy other software.
As a rule, we test only with the programs a given scanner comes with. If a scanner doesn't come with OCR software, for example, we don't run an OCR test. However, we do take note of how well the scanner integrates with third-party software such as photo editing apps and document management systems.
What's in Our Testing Suite
Although the exact mix of tests that we run depends on the particular scanner and the software it comes with, the tests are drawn from a standard suite, with tests for pure text documents, business documents with embedded graphics, business cards, photographic prints, slides, and strips of film. (Slide and film scanning aren't as prevalent as they were a while back, so we don't often test these functions.)
For testing OCR capability, we scan several pages of text samples with a single font on each page in a variety of sizes, and we report accuracy in terms of the smallest size for each font that the scanner could read without a mistake. We also look for the presence or absence of an automatic document feeder (ADF) or single-sheet manual feed, the ability to duplex (read both sides of each page), and potentially useful software features, like digital enhancements that can increase both readability and accuracy, including, for example, the ability to ignore background colors.
For testing document scanning, we look at whether the scanner has an ADF or sheet feeder; how many pages the ADF can handle; whether the scanner can duplex; whether the driver or bundled software can save a scan directly to PDF format; and whether the package can scan, OCR, and save to searchable PDF format. We also look for, and at, any bundled document management and indexing programs.
Recommended by Our Editors
To test speed for document scanning, we time a series of scans, using multiple-page documents for scanners with automatic document feeders (ADFs) or single pages for scanners that lack ADFs.
For scanners with ADFs, we report the times in pages per minute (ppm) for scanning in simplex (one-sided mode) to an image PDF file; in images per minute (ipm—with one image on each side of the page) for scanning in duplex to an image PDF file; and in minutes and seconds for scanning to a searchable PDF file, which is generally the preferred format for document scanning. We also report the difference in time, in minutes and seconds, between scanning to image PDF and searchable PDF formats.
For testing business-card scanning and management, we look for the presence or absence of an ADF or sheet feeder suitable for business cards, the ability to read business cards accurately and parse the text into the right fields in a database, and the ability to synchronize with other programs—most notably Microsoft Outlook.
For testing photo scanning, we scan designated test photos and look at scan quality as well as software features such as digital dust removal, scratch removal, grain removal, and color restoration that can improve the results. In addition, we consider the capabilities of any bundled photo editor and related software, such as photo-album programs, and the presence or absence of batch scanning features. If the photo has to go through a sheet feeder, we check whether the scanner offers a straight-through path and comes with a protective plastic sleeve to minimize the chances of damage.
For testing slide scanning, we scan our test slides and look at many of the same hardware and software features as for photos, but as they apply to slides. We also test batch scanning for multiple slides and check the maximum optical resolution, which determines how large an image you can print at reasonably high quality.
For testing film scanning, which we define as strips of film, whether positive or negative, we scan a test image from a strip of film and look at essentially the same features as for slides, plus the number and range of film sizes the scanner can handle. We test film separately from slides, because not all scanners can handle both, and because a given scanner may have an important feature, such as an autoloader, that works with slides only or strips of film only.
Finally, we run a few other tests. We analyze ease of hardware setup and software installation; ease of use of the driver and bundled software; convenience features, such as one-touch scan buttons; options to scan and fax, scan and e-mail, and scan to the cloud; overall speed, which includes how well the scanner saves time with features such as batch scanning (scanning multiple originals at once, each to its own file); and the availability of drivers for common standards, which let the scanner work with the widest possible range of application software.
Thanks to our thorough and consistent testing, which lets us directly compare competing scanner models, we can confidently stand by our ratings and evaluations—and, of course, our recommendations for the best scanners.