Advances in Fingerprint Technology.pdf

Figure 2.2 Osborn grid method.
Seymour Trace Method
In the Seymour trace method, the latent and inked prints are both copied
on tracing paper. 5 The two tracings are then compared by superimposing
one over the other and viewing them with backlighting. By tracing each point
between the latent and the known print, a comparison is made.
Photographic Strip Method
The photographic strip method also involves the use of photographic enlargements.
6 The positioning and alignment of both prints in the enlargements
must be in as close agreement as possible. The enlargement of the inked print
is secured to a rigid mount. The enlargement of the latent print is then cut
in lateral strips and placed over the enlargement of the inked print. The two
enlargements must be fastened together in perfect conjunction. The identity
is then demonstrated by removing the strips of the latent enlargement one
at a time, exposing the inked print below.
Polygon Method
The polygon method (Figure 2.3), also called the “pincushion” method, of
demonstrating identity also requires photographic enlargements of the latent
and inked prints; both must be made at the same scale. 7-9 Small pinpoint
holes are punched in each enlargement at the corresponding ridge characteristics.
The enlargements are then reversed and straight lines are drawn
connecting the points punched. The geometric configuration of each print
is then compared. If the polygon of pin holes between the latent and the ink
print matches, the identity is declared.