Advances in Fingerprint Technology.pdf

extreme variability of friction ridge patterns, ridge characteristics, intrinsic
ridge shapes, and pore locations. Traditionally, fingerprint individuality has
been discussed with reference to the ridge characteristics, or fingerprint
minutiae. These characteristics are now classified as a portion of Second Level
Detail, which encompasses the paths and the ridges (along with any scars,
incipient ridges, or flexion creases). 6 The relative position, orientation, and
type of fingerprint minutiae within the ridge pattern are extremely variable,
even among identical twins. This is known to be because, in addition to
overall genetic influences, 7 the positions of minutiae within the friction ridge
pattern are determined by the highly variable dynamics of fetal hand development.
The extreme variability in minutiae among fingerprints is readily
appreciated if one takes prints from different individuals and an attempt is
made to successively find a correspondence in a group of three, then four,
then five minutiae. A correspondence in four minutiae might well be found
upon diligent, extended effort when comparing the full set of prints of one
individual with those of another person. (In doing this, one might well ignore
other, finer detail that distinguishes the two prints, but then again, such detail
might well be absent in prints of less clarity.) For a legitimate correspondence
of five points between different individuals, it might mean searching for
weeks among many different individuals. A correspondence of six points
might be a lifetime’s search. Unfortunately, although there is extensive collective
experience among casework examiners, 8 there has been no systematic
study such as that described above.
Nonetheless, the fingerprint examiner’s opinion of absolute identification
is a logical extension of this process, including as its final step a “leap
of faith” where, in the critical, experienced (but subjective) judgment of the
examiner, it is inconceivable that the fingerprint could have come from
another person’s finger.
Important factors that enter into the professional judgment of an absolute
identification are
1. The extent of the prints (area and number of ridge characteristics)
2. The clarity of the prints
3. The presence or absence of dissimilarities
4. The examiner’s training, experience, skill, and ethics
Limitations of Traditional Points of Comparison
The number of corresponding minutiae, or “points,” is a convenient, somewhat
objective feature to use when discussing fingerprint comparisons.
Because of their nearly universal use when describing fingerprint comparisons,
and because of the historical acceptance of 12 “points” as a conclusive