2.
The naming of any particular pattern is known
as pattern interpretation.
Fingerprint classification generally refers to the
derived for a complete set of ten fingerprint
patterns:
Henry with FBI Extensions
NCIC
Source: Institute of Applied Science
2
4.
Recurving ridges are ridges that curve back to
the direction from which they started
Converging ridges are angles formed by on
ridge abutting another ridge
An appendage is a short ridge connects to a
recurving ridge at the recurve at a right angle
thus is interpreted as ruining the recurve
Source: Institute of Applied Science
4
5.
Divurging ridges are ridges which run side by
side suddenly separating and flowing in
opposite directions.
Bifurcating ridges is when a single ridge splits
into two ridges
Source: Institute of Applied Science
5
6.
The pattern area of a fingerprint is that part
which lies within the area surrounded by “type
lines”
Type lines are the basic boundaries of most
fingerprints.
Formed by ridges which run parallel from the lower
corners of the pattern and flowing inward and
upward toward the edge of the pattern area, where
they diverge and separate, then surround or ten to
surround the pattern area.
Source: Institute of Applied Science
6
7.
Whenever the ridge that forms a type line ends
suddenly, the next ridge immediately outside of
it is taken as its continuation.
The “pattern area” is that part of the fingerprint
in which are found the cores, deltas, and other
ridges pertaining to a particular pattern type.
Source: Institute of Applied Science
7
8.
A “delta” is a point on the first ridge formation
at or directly in front of the divergence of the
type lines.
Sometimes the delta ridge may run into one of
the”type lines”, but the delta can never be located
exactly on one of the “type lines”
All bifurcations are not “deltas”, nor are all delta
formations “deltas”
To be a “delta”, a bifurcation must be the first ridge
formation in front of the divergence of the “type
lines”, and the bifurcation must open up toward the
pattern area.
Source: Institute of Applied Science
8
9.
Sometimes the first ridge in front of the divergence
will have more than one bifurcation, in such a pattern
the bifurcation nearest the core is considered as being
the “delta”
Sometimes you will see patterns in which there is a
ridge between and parallel to the “type lines”
running into the pattern area.
The deciding point is the origin of this ridge.
If the ridge is wholly located within the pattern area,
the delta is located on the end nearer to the divergence
Should this ridge originate outside the pattern area, the
delta is located at the end nearer the core.
Source: Institute of Applied Science
9
10.
Whenever there is a choice between a bifurcation
and some other ridge formation as the location of the
delta, the bifurcation is always taken as the delta.
EXCEPTION: With one exception the two legs of the
same bifurcation are never “type lines”. The exception
occurs when the bifurcation opens toward the core, but
is so far outside the pattern area that the legs of the
bifurcation run parallel for some distance before they
diverge. In such a pattern the legs of the bifurcation are
taken as “type lines”.
Source: Institute of Applied Science
10
11.
REMEMBER THAT TYPE LINES
THEMSELVES ARE NEVER CONSIDERED AS
THE DELTA, BUT IT IS THE RIDGE
FORMATION IN FRONT OF THE
DIVERGENCE OF THE TYPED LINES THAT
IS THE DELTA.
Source: Institute of Applied Science
11
12.
The core is the center or the heart of the pattern
area.
Cores in loops are formed in a variety of ways,
but they are always found either on or within
the innermost recurving loop.
A loop pattern may have one single recurving
ridge in the center, called a staple or it might
have several staples, one inside of another.
Source: Institute of Applied Science
12
13.
It might have a single ending ridge, in the
center of a recurving ridge known as a rod or
bar.
When a staple encloses one or more bars it is
called an envelope
The are two positions on a recurving ridge
known as shoulders.
These are on each side of a recurving ridge or loop
where the ridge definitely begins and stops its
recurve.
Source: Institute of Applied Science
13
14.
In patterns in which there is only a single
recurving ridge, the core is at the shoulder on
the farther side of the loop from the delta.
If the pattern has two or more looping ridges in
the core area , that is two staples within each
other, without a rod inside the innermost
staple, the core is located at the shoulder of the
innermost staple on the side farther from the
delta.
Source: Institute of Applied Science
14
15.
When the pattern under consideration shows
one rod or bar within the innermost loop ridge,
the top of that rod is the core.
Should the innermost loop ridge enclose two
bars, the top of the one farther from the delta is
the core.
Should an odd number of rods appear within
the center of the center-most one is the core.
Source: Institute of Applied Science
15
16.
Should four or six rods show up with the
innermost loop ridge, we consider only the two
innermost rods and consider the one farther
from the delta as the core.
Should two loops intersect in the center of the
pattern area we consider the two recurving
ridges within the pattern to be rods and
consider the one farthest from the delta to be
the core.
Source: Institute of Applied Science
16
17.
Only those rods which rise to or above the
shoulders of the center loop are taken into
consideration.
Source: Institute of Applied Science
17
18.
A loop is a pattern in which one or more of the
ridges start at one side of the pattern, run
toward the upper corner on the opposite side,
then recurve and start back toward the side
from which they came originally, forming a
loop with a core in the center and a delta at the
edge of the pattern area.
Loops are the most common fingerprint pattern
appearing in 60% of all patterns.
Ulnar loops are more common than radial
loops
Source: Institute of Applied Science
18
19.
To be a loop, a pattern must fulfill four
requirements:
It must have a core
It must have a delta
It must have a recurving ridge that passes between
the delta and the core.
It must have a ridge count of at least one.
Source: Institute of Applied Science
19
20.
Ridge counting refers to the process of
counting ridges that touch an imaginary line
drawn between the core and delta of a loop.
The core and delta are NOT counted.
Source: Institute of Applied Science
20
21.
There are two types of loops.
The Ulnar Loop flows from the little finger side
of the hand and recurves back to that side with
the open end pointing in the direction of the
little finger
The Radial Loop flows from the thumb side of
the hand and recurves back to that side with
the open end pointing in the direction of the
thumb.
Source: Institute of Applied Science
21
