Fingerprint analysis. Comparison of fingerprints with characteristic features marked. Fingerprints are classified into three basic types and are then further classified by features which are called minutia points or ridge characteristics. There are around thirty different types of these. The ridge characteristics are considered unique for each individual. As few as seven ridge characteristics in the same position are needed for a positive identification. Computer analysis has enabled very large numbers of fingerprints to be compared with great speed, allowing suspects to be linked to any unsolved crime on record. Fingerprints are water and oil patterns formed by skin ridges.