User guide

S900 User Guide
Correcting Wet or Dry Fingerprint Images:
When the temperature is rigid or when hands have just been washed,
fingerprints often become very dry. In this case, the user should
moisturize his/her fingerprint simply by breathing on the fleshy pad of
his/her fingertip prior to placing his/her finger on the sensor. The
moisture from his/her breath should improve the recognition of his/her
fingerprint.
Conversely, if the fingerprint is too wet, the ridges and valleys are
rendered indistinguishable. The lack of recognizable minutiae causes
wet fingerprints to be rejected by the S900. This can be remedied simply
by swiping the finger on a clean dry towel or cloth.
How much pressure is required for a good-quality
fingerprint?
If too much pressure is applied when pressing down on the sensor, the
finger’s ridges become pressed together and create an unrecognizable
image. Applying too much pressure (similar to fingerprints that are too
wet) will create a “blurred” image which the S900 sensor might not
recognize.
If too little pressure is applied, the resulting image will be similar to the
dry fingerprint and unidentifiable. Issues related to moisture and
pressure can easily be addressed with practice and users getting a feel of
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