Scanners of various flavors still exist, of course, but there's a lot less need for the average person to own one. Your recent-ish photographs are all going to be digital, and it's rare that most people will need to scan much of anything else until they stumble onto a collection of family photos or a cache of historical documents that need preservation. When you do need to scan a document or two, where do you turn outside of stopping by the local FedEx Office location?
AdvertisementToday's smartphone cameras are good enough that, with the right software, they can function pretty well as scanners. It's not what they're made for, though, so finding that software is key. Specifically, the software, once it knows the location of the corners of the image or document being scanned, will "flatten" out the image in software and crop it down to just the physical image in question.
Finding some kind of basic scanning app is pretty trivial: Google has PhotoScan, for example, the rare Google app not bundled with Android, and scanning functionality is available in various camera apps, including Samsung. However, what if you need something optimized for documents? Something with well-integrated PDF output support, or text recognition? There are some great document scanners you can get for free on Android.
Advertisement 
Of course, Adobe — the inventor of the PDF file format — has a document scanning app, simply named Adobe Scan. The core functionality is completely free with no ads, and no watermarking of exported PDFs, plus it saves everything to your free 5 GB of storage on an Adobe Document Cloud account.
AdvertisementThere's a paid tier, and it's a bit stiff at $9.99 per month, particularly since the extra functionality you could pay for is either included in the free, web-based version of Document Cloud (like PDF compression and text recognition), or easily attainable through other free apps (like combining PDFs).
As for the actual scanning process, Adobe Scan tries to automate as much as it can. There's no shutter button, as it takes the picture when it feels it's properly detected the document. Its corner detection is also pretty good, but not perfect. That said, in testing, it wasn't the best when it came to image quality in terms of taking and flattening out the document, producing the kind of warbly result that is commonly a problem with this kind of app.
AdvertisementRegardless, it's still a very high quality app overall that delivers a ton of value to free users, without any trade-offs in terms of headaches like nag screens or ads.
If CamScanner isn't the longest-running document scanner app for Android, then it's close. If there's anything close to a name brand in this space, it's CamScanner, and with good reason: With over 100 million downloads on the Google Play Store, it averages a 4.8 out of 5 rating from 4.51 million reviews. The free version is ad-supported, and places a watermark on the bottom-right corner of each page of a PDF (but not non-paginated image files) among other limitations. However, it's still feature-packed and, of the apps tested, has the best image quality.
AdvertisementThe document-flattening technology is far from perfect, often resulting in warbly-looking images where things like blown-out lines betray the quality. CamScanner, though, delivers a significantly more balanced and straightened picture than any other app tested. As long as you're dealing with documents that have clear margins or don't mind collating individual pages into a PDF yourself, then you can trust that CamScanner is going to give you the highest quality output for free.
Going beyond that, though, CamScanner is pretty feature-packed. It has a book-scanning mode for capturing two pages at a time, and a whiteboard scanner for taking a picture of one without glare. It also offers the ability to do its magic on existing image files the same way that Adobe Scan does. If you'd like to subscribe to the paid version to remove the ads, PDF watermarks, and other limitations, it will cost you $39.99 per year.
