Short answer: A good enrolment comes down to the finger: the pad flat on the sensor, a clean lift between placements, and a slightly different position each time. Whether you enrol on your phone or at an enrolment station, the card must stay completely still during each capture – on a phone you hold it still yourself; in the station's smartcard reader, it will hold it for you.
The sensor
The sensor is the small black square in the bottom-right corner of the card. It needs a good, flat touch, and it needs the card to stay still while you touch it.
Making good captures
- Rest the pad of your finger flat on the sensor, covering the whole square. Do not use the tip, the side or your fingernail.
- Press firmly enough for full contact – but not so hard that the card moves.
- Between each placement, lift your finger clean off the sensor, then place it again. Do not slide or drag.
- Slightly vary where your finger lands each time – up, down, a little left or right. This change of position of your finger builds a wider map of your fingerprint, which makes every future scan more reliable.
- Keep the card still the entire time. Even a small shift can spoil a capture and require a retry.
- A failed capture only prompts a retry – there is no limit on enrolment attempts.
Keeping the card still
On a phone, the card is held against the phone's NFC antenna, so keeping it still requires the most care. Hold it flat, and press the sensor gently enough that the card does not lift or tilt away from the phone. NFC antenna placement differs by platform. See: iPhone and Android.
At an enrolment station, the card is inserted into the reader, which holds it steady with the sensor exposed. Leave it in place and focus on finger placement. See: Centralised enrolment – enrolment station.
If captures keep failing
- Very dry, wet or greasy fingers all read poorly. Wipe your finger with a dry cloth – or breathe on it if your skin is very dry.
- Clean the sensor gently with a dry, soft cloth. Smudges and grime reduce contact quality.
- Try a different finger. A finger with a fresh cut, a callus or a healing scar may not enrol well until it heals.