Ridge flow refers to the directional arrangement of friction ridges and is most often used for pattern-level screening of fingerprints. Ridge flow provides more specific detail than pattern classification and can be used more effectively on partial fingerprints. It can be used by AFIS algorithms as an end matcher to refine the list of candidates produced by the feature matchers.

Ridge flow map markup, as shown in Figure 1, is typically started using automated tools to extract the flow directions from the image. This automated markup is then modified by the examiner (if necessary) to correct inaccuracies in the automated flow map. A latent corresponding to the right half of this print would appear to be a left slant loop rather than a double loop whorl; unlike traditional pattern classification, ridge flow maps permit rapid automatic comparison of such partial prints.

Ridge flow is marked if EFS Profile 3: Detailed Markup Search Profile is to be used. No exercises are provided for Ridge Flow Map markup.