How Dirty Fingers Can Actually Make It Harder To Unlock Your Phone

How Dirty Fingers Can Actually Make It Harder To Unlock Your Phone

Fingerprint scanners do have a “kryptonite” - your dirty fingers. That’s a bit much to say, no? 

It’s really not. 

For a scanner to read your prints properly, it should be free of dirt, debris or any particles that block its optics. Just like a window coated with grime, a fingerprint scanner can’t “see” clearly beyond the layer of dirt, making it harder to read your unique finger signature. But all of us carry a significant amount of contaminants on our fingers even if we can’t see them.  

Under the Microscope: Finger Contaminants That Get On the Screen

Although there are three types of fingerprint scanners - optical, capacitive and ultrasonic - they all essentially work by scanning the unique pattern of ridges. Once verified and indexed, the print becomes its own password. 

Dirt can affect them all, but some phones use more powerful scanners than others. 

Now no offense to you, but your hands aren’t as clean as you think. If you disagree, you probably don’t remember all of the places your hands have been. Just think about your average day and all of your interactions. 

  • Shaking hands at work or in public
  • Gripping the poles on the bus/subway
  • Holding the escalator rail at a mall
  • Touching fruits/veggies and food items at the grocery store
  • Cleaning dirty surfaces (ie. bathroom, kitchens)
  • Using cosmetic and skincare products
  • Grooming and cleaning yourself (whatever that entails)

Of course, there are many places and scenarios that expose your fingers to contaminants, some are too gross to mention. With that said, some contaminants are repeat offenders when it comes reducing fingerprint scanning ability. 

  • Sweat
  • Condensation
  • Dust/dirt
  • Oils (from lotion and cosmetics)
  • Scratches (not a contaminant but still problematic)

For the most part, a fingerprint reader on a phone can recognize your prints even in the presence of some contaminants. 

But when there’s a build-up of excess particles, whether it’s from sweat, oils or something else, the scanner can’t detect the ridges of your prints as easily. This is why you can get locked out of their phone and maybe even see a message that says “fingerprint scanner dirty”. 

Solution For Cleaning a Dirty Fingerprint Scanner

The easy solution for fixing a dirty fingerprint scanner, of course, is to clean it. However, if you look closely enough at your device, you might notice that finger smudges tend to linger on the screen. And if you try to rub them off, they don’t go anywhere - if anything, you just create new streaks. 

So the best way to get rid of these oil slicks is to use a cleaning agent that dissolves the compounds found in oily substances. Our patented ScreenShine is a great product for this. One of its many capabilities is reducing the number of fingerprint smudges that appear on your phone. 

The invisible coating the ScreenShine leaves behind forms a barrier that keeps oils, condensation and sweat from building up on your phone. The result is a clean scanner that sees nothing but your unique fingerprint. 

Fingerprint Not Recognized? Clean It To Unlock It

If you ever have issues unlocking your phone with a fingerprint, check to see if the screen itself is dirty or smudged with oil. And of course, if your phone is telling you that it’s dirty, then pick up a cloth and wipe the debris off. 

Also, practice basic hygiene. Wash your hands regularly, especially after coming in contact with the contaminants mentioned in this post. Cleaner hands will transfer less dirt and oils which obscure your fingerprint readers.