Samsung SM-A505FN/DS User Manual page 184

Settings
For better fingerprint recognition
When you scan your fingerprints on the device, be aware of the following conditions that
may affect the feature's performance:
The device may not recognise fingerprints that are affected by wrinkles or scars.
The device may not recognise fingerprints from small or thin fingers.
To improve recognition performance, register fingerprints of the hand used most often to
perform tasks on the device.
Your device has a built-in fingerprint recognition sensor at the bottom centre of
the screen. Ensure that the screen protector or the touchscreen on the fingerprint
recognition sensor area is not scratched or damaged by objects, such as coins, keys, pens,
and necklaces.
Ensure that the fingerprint recognition sensor area at the bottom centre of the screen
and your fingers are clean and dry.
If you bend your finger or use a fingertip, the device may not recognise your fingerprints.
Press the screen so that your fingertip spreads over the wide surface of the fingerprint
recognition area.
Registering fingerprints
1
On the Settings screen, tap Biometrics and security
2
Unlock the screen using the preset screen lock method.
If you have not set a screen lock method, create one.
Fingerprints.
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