CLASSIFICATION
The modern system of fingerprint classification is based on Henry’s original design, which could process a maximum of 100,000 sets of prints, with modifications by the FBI to allow for the huge number of entries that have accumulated over the years. The FBI Criminal Justice Information Services (CJIS) currently has over 80 million fingerprints stored in its files. The modern fingerprint classification consists of a primary classification that encodes fingerprint pattern information into two numbers derived as follows. All arches and loops are considered “nonnumerical” patterns and are given a value of zero. Whorls are given the values depending on which finger they appear, as shown in Table 1. The values are summed, with one added to both groups, and the resulting primary classification is displayed like a fraction:
If, for example, all of an individual’s fingers had whorls, the formula would look like this:
16+8+4+2+1+1/16+8+4+2+1+1=32/32
If all of an individual’s fingers had arches or loops instead, the formula would be as follows:
0+0+0+0+0+1/0+0+0+0+0+1=1/1
In and of itself, a primary classification is just that: class evidence. The primary classification was originally devised to sort individuals into smaller, more easily searched categories; this, of course, was when fingerprints were searched by hand. Additional subdivisions of the classification scheme may be used, but they still only serve as a sieve through which to organize and efficiently search through filed prints. Comparison of minutiae and higher level details is the only method for fingerprint identification. The problem with storing and sorting fingerprints using only the Henry-FBI classification system is that while the system stores all 10 prints as a set, rarely are full sets of fingerprints found at a crime scene. To search through even a moderately sized database of 10 print sets for an individual print would take too long and be too prone to error. Many agencies used to keep single-print files that contained the separate fingerprints of only the most frequent locally repeating criminals.
Table 1 Values for Fingers in the Henry Classification System
