The Classification Formula



At this point it is necessary to mention that when prints are

classified, markings are indicated at the bottom of each finger block

to reflect the type. The following symbols are used:



- Under the index fingers the appropriate capital letters

should be placed for every pattern except the ulnar loop.



- Under all other fingers, the appropriate small letter

should be placed for every pattern except the ulnar loop and

the whorl as follows:



Arch a

Tented Arch t

Radial Loop r



- Ulnar loops in any finger are designated by a diagonal

line slanting in the direction of the loop.



- Whorls in any finger are designated by the letter W. The

classification formula may be composed of the following

divisions:



1. Primary

2. Secondary

3. Subsecondary

4. Major

5. Final

6. Key



The positions in the classification line for these divisions when

completely applied are as illustrated:



Key Major Primary Secondary Subsecondary Final

--------------------------------------------------------------------------

Divisions Classification Classification Classification



20 M 1 U IOI 10

--------------------------------------------------------------------------

L 1 U IOI



Second subsecondary

classification

Key Major Primary Secondary Subsecondary Final

--------------------------------------------------------------------------

Divisions Classification Classification Classification



SLM

---

MMS

4 O 5 U IOI 10

--------------------------------------------------------------------------

I 17 U IOI



THE PRIMARY CLASSIFICATION: For the purpose of obtaining the primary

classification, numerical values are assigned to each of the ten

finger spaces as shown in figure 347. Wherever a whorl appears it

assumes the value of the space in which it is found. Spaces in which

types of patterns other than whorls are present are disregarded in

computing the primary.



The values are assigned as follows:



Fingers No. 1 and No. 2 16



Fingers No. 3 and No. 4 8



Fingers No. 5 and No. 6 4



Fingers No. 7 and No. 8 2



Fingers No. 9 and No. 10 1







LEAVE THIS SPACE BLANK SEX

+--------------+

FBI No. RACE

+--------------+ LAST NAME FIRST NAME MIDDLE NAME

---------------------------------------------------------------+----------

SIGNATURE OF PERSON CONTRIBUTOR ALIASES HT. WT.

FINGERPRINTED AND ADDRESS (IN.)



DATE OF

----------------------------- BIRTH

RESIDENCE OF PERSON

FINGERPRINTED HAIR EYES



--------------------------------------------------------------------------

OCCUPATION ARREST NUMBERLEAVE THIS SPACE BLANK



------------------------------------------

SCARS AND MARKS PLACE OF

BIRTH 29

-------------CLASS

-----------------------------CITIZENSHIP 19

SIGNATURE OF OFFICIAL DATE

TAKING FINGERPRINTS CHECK IF

NO CRIMINALREF.

RECORD IS

DESIRED

---------------------------------------------------------------------------

1. RIGHT THUMB2. RIGHT INDEX3. RIGHT 4. RIGHT RING 5. RIGHT LITTLE

MIDDLE

N 16 N 8

[Illustration][Illustration][Illustration][Illustration][Illustration]

D 16 D 8 D 4

---------------------------------------------------------------------------

W W \ W \

---------------------------------------------------------------------------

1. LEFT THUMB 2. LEFT INDEX 3. LEFT 4. LEFT RING 5. LEFT LITTLE

N 4 MIDDLE

N 2 N 1

[Illustration][Illustration][Illustration][Illustration][Illustration]

D 2 D 1

---------------------------------------------------------------------------

W W / / /

---------------------------------------------------------------------------



In figure 347, it will be observed that the odd fingers (Nos. 1, 3, 5,

7, 9) contain the letter D, and the even fingers (Nos. 2, 4, 6, 8, 10)

contain the letter N. The D indicates that the values of these fingers

relate to the denominator, the N that they relate to the numerator.

The summation of the numerical values of the whorl type patterns, if

any, appearing in fingers 1, 3, 5, 7, 9, plus one, is the denominator

of the primary. The summation of the values of the whorls, if any, in

fingers 2, 4, 6, 8, 10, plus one, is the numerator of the primary.

Where no whorl appears in a set of impressions, the primary,

therefore, would be 1 over 1. The 1 that is assigned to the numerator

and the denominator when no whorls appear is also added, for

consistency, to the value of the whorls when they do appear. It will

be understood why it was originally assigned to the no-whorl group

when it is considered how easily a zero might be confused with an O,

which is the symbol used for an outer whorl tracing.



To obtain the primary for the prints in figure 347, the number of

whorls appearing in the odd fingers is ascertained to be 2. Their

positions are noted (1 in No. 1 and 1 in No. 7) and the values

assigned to whorls appearing in those fingers are added together (16

plus 2 = 18). To this sum the arbitrary 1 is added, giving us the

total of 19, which constitutes the denominator for this set of prints.

To get the numerator, it is ascertained that there are 3 whorls

appearing in the even fingers (2, 4 and 6), the values of which are

added together (16 plus 8 plus 4 = 28). To this sum the 1 is added,

giving a numerator of 29, and a complete primary of 29 over 19.



By the word whorl is meant all types of whorls, including plain

whorls, central pocket loops, double loops and accidentals. The

tracing of the whorl does not enter into the determination of the

primary.



The method of obtaining the primary can probably be shown best by

illustrations. For example, assume that there is a whorl in the right

index finger only. The value of a whorl in this finger is 16. When 1

over 1 is added the resulting primary is 17 over 1. If a whorl appears

in the right thumb and right index finger, the value is 16 over 16

plus 1 over 1 giving a primary of 17 over 17. If whorls appear in both

index fingers, the value is 16 over 2 plus 1 over 1 giving a primary

of 17 over 3. When whorls appear in both thumbs and both index

fingers, the primary is 21 over 19 and is obtained by the addition 16

plus 4 plus 1 over 16 plus 2 plus 1. If whorls appear in all 10

fingers, the primary is 32 over 32 (16 plus 8 plus 4 plus 2 plus 1

plus 1 over 16 plus 8 plus 4 plus 2 plus 1 plus 1). It will be noted

that the primary classifications extend from 1 over 1 in the no-whorl

group to 32 over 32 in the all-whorl group, providing 1,024 possible

combinations. This does not mean that there are 1,024 even

subdivisions of prints according to these primaries. Just as there is

a preponderance of loops when the types of patterns are considered,

there is also a preponderance of certain primaries, notably: the 1

over 1 primary, or no-whorl group; the 17 denominator; the 19

denominator; the 28 denominator, of which the 31 over 28 group is the

largest; and the 32 denominator, including 2 large primary groups

namely, 31 over 32 and 32 over 32. As a matter of fact, the 1 over 1

group, as a whole, contains over 25 percent of the total number of

prints filed in the FBI. On the other hand, there are a number of

primaries which rarely appear. It follows, therefore, that when a

print is classified in one of these larger groups it is necessary to

complete the classification to a greater extent than is necessary in

the more unusual primaries, so that the group to be searched is small

enough for convenience.



In connection with the counting of whorl values to obtain the primary,

it might be noted that when the whorls outnumber the other patterns

more speed can be achieved by counting those patterns and subtracting

rather than by adding the whorls. This procedure should not be

followed until enough experience is acquired so that it may be noted

at a glance where whorls are not present.



The experienced classifier can tell in what fingers whorls are present

by a glance at a primary classification. For example, a primary of 5

over 17 could mean that there are whorls in the thumbs only.







LEAVE THIS SPACE BLANK SEX

+--------------+

FBI No. RACE

+--------------+ LAST NAME FIRST NAME MIDDLE NAME

---------------------------------------------------------------+----------

SIGNATURE OF PERSON CONTRIBUTOR ALIASES HT. WT.

FINGERPRINTED AND ADDRESS (IN.)



DATE OF

----------------------------- BIRTH

RESIDENCE OF PERSON

FINGERPRINTED HAIR EYES



--------------------------------------------------------------------------

OCCUPATION ARREST NUMBERLEAVE THIS SPACE BLANK



------------------------------------------

SCARS AND MARKS PLACE OF

BIRTH 9 R

-------------CLASS

-----------------------------CITIZENSHIP 2 R

SIGNATURE OF OFFICIAL DATE

TAKING FINGERPRINTS CHECK IF

NO CRIMINALREF.

RECORD IS

DESIRED

---------------------------------------------------------------------------

1. RIGHT THUMB2. RIGHT INDEX3. RIGHT 4. RIGHT RING 5. RIGHT LITTLE

MIDDLE



[Illustration][Illustration][Illustration][Illustration][Illustration]



---------------------------------------------------------------------------

\ R \ W \

---------------------------------------------------------------------------

1. LEFT THUMB 2. LEFT INDEX 3. LEFT M4. LEFT RING 5. LEFT LITTLE

18 10 MIDDLE I I 13



[Illustration][Illustration][Illustration][Illustration][Illustration]



---------------------------------------------------------------------------

/ R / W /

---------------------------------------------------------------------------



THE SECONDARY CLASSIFICATION: After the primary classification, the

fingerprints are subdivided further by using a secondary

classification. Before going into detail, it should be noted that

after the primary is obtained the entire remaining portion of the

classification formula is based upon the arrangement of the

impressions appearing in the right hand as the numerator over the

impressions appearing in the left hand as the denominator. The

arrangement of the even over the uneven fingers is discarded after the

primary is obtained. The secondary classification appears just to the

right of the fractional numerals which represent the primary. It is

shown in the formula by capital letters representing the basic types

of patterns appearing in the index fingers of each hand, that of the

right hand being the numerator and that of the left hand being the

denominator (fig. 348). There are five basic types of patterns which

can appear.



1. Arch A

2. Tented Arch T

3. Radial Loop R

4. Ulnar Loop U

5. Whorl W







LEAVE THIS SPACE BLANK SEX

+--------------+

FBI No. RACE

+--------------+ LAST NAME FIRST NAME MIDDLE NAME

---------------------------------------------------------------+----------

SIGNATURE OF PERSON CONTRIBUTOR ALIASES HT. WT.

FINGERPRINTED AND ADDRESS (IN.)



DATE OF

----------------------------- BIRTH

RESIDENCE OF PERSON

FINGERPRINTED HAIR EYES



--------------------------------------------------------------------------

OCCUPATION ARREST NUMBERLEAVE THIS SPACE BLANK



------------------------------------------

SCARS AND MARKS PLACE OF

BIRTH 1 R

-------------CLASS

-----------------------------CITIZENSHIP 1 aU

SIGNATURE OF OFFICIAL DATE

TAKING FINGERPRINTS CHECK IF

NO CRIMINALREF.

RECORD IS

DESIRED

---------------------------------------------------------------------------

1. RIGHT THUMB2. RIGHT INDEX3. RIGHT 4. RIGHT RING 5. RIGHT LITTLE

MIDDLE



[Illustration][Illustration][Illustration][Illustration][Illustration]



---------------------------------------------------------------------------

\ R \ \ \

---------------------------------------------------------------------------

1. LEFT THUMB 2. LEFT INDEX 3. LEFT M4. LEFT RING 5. LEFT LITTLE

18 10 MIDDLE I I 13



[Illustration][Illustration][Illustration][Illustration][Illustration]



---------------------------------------------------------------------------

a / / / /

---------------------------------------------------------------------------



SECONDARY CLASSIFICATION (SMALL-LETTER GROUP): Prints with an arch or

tented arch in any finger or a radial loop in any except the index

fingers constitute the small-letter group of the secondary

classification. Such small letters, with the exception of those

appearing in the index fingers, are brought up into the classification

formula in their proper relative positions immediately adjacent to the

index fingers (fig. 349). A dash is used to indicate the absence of

each small letter between the index fingers and another small letter

or between two small letters, as



1 aUa-t 1 aU-t.

------- and ------

1 R-a 1 U-a



Thus, if a radial loop appears in the right thumb, the small letter

r would be brought up in the numerator column of the classification

formula and placed just to the left of the capital letter representing

the index finger. Similarly, if an arch or tented arch or a radial

loop would appear in the middle, ring, or little finger of the hand,

the small letter representing such a pattern would be placed on the

classification line to the right of the secondary in the numerator

column if the letter is present in the right hand, and in the

denominator column if in the left hand. When two or more small letters

of the same type occur immediately adjacent to each other, they are

indicated thus:



1 rU-2a 1 aTa-a.

------- and -------

1 tU3a 1 tA2at



The small-letter groups are of vital importance to the classification

system, as they are of relatively infrequent occurrence, constituting

approximately 7 to 10 percent of all patterns. Generally speaking,

since these patterns are of such rare occurrence, their very presence

often enables the classifier to dispense with the usual subsecondary

classification and the major division which in the majority of cases

are used in the larger groups.



THE SUBSECONDARY CLASSIFICATION (GROUPING OF LOOPS AND WHORLS): In

classifying prints it is necessary to subdivide the secondary groups.

This is accomplished by grouping according to the ridge counts of

loops and the ridge tracings of whorls. The first of the groups filed

in order, which it will be necessary to so subdivide, would ordinarily

be the



1 R

---

1 R



group where no small letters appear. The Federal Bureau of

Investigation, however, has found it necessary to extend this division

to many of the small-letter groups which become cumbersome. The

subsecondary is placed on the classification line just to the right of

the secondary. Ridge counts are translated into small and large,

represented by symbols I and O. The whorl tracings are brought up as

I, M, or O denoting inner, meeting or outer ridge tracings of the

whorl types. Only six fingers may be involved in the subsecondary--numbers

2, 3, 4, 7, 8, and 9.



A ridge count of 1 to 9, inclusive, in the index fingers is brought up

into the subsecondary formula as I. A count of 10 or more is brought

up as O. In the middle fingers a count of from 1 to 10, inclusive, is

brought up as I, and 11 or more is O. In the ring fingers a count of

from 1 to 13 is brought up as I, and 14 or more is O. A loop

subsecondary could appear in the classification formula as



OIO.

---

IIO



Analyzing this example of a subsecondary, one will know that in the

index, middle, and ring fingers of the right hand there are counts of

over 9, under 11, and over 13, while in the left hand there are in the

index, middle, and ring fingers, counts of under 10, under 11, over

13, respectively. The subsecondary classification, therefore, relates

to the groupings of the prints, and no difficulty should be

experienced in ascertaining whether the I and O arrangement in the

subsecondary relates to loops or whorls when analyzing a

classification, because this information can be obtained from the

primary classification. Figure 350 is an example illustrating the

subsecondary in addition to other divisions of the classification

formula.







LEAVE THIS SPACE BLANK SEX

+--------------+

FBI No. RACE

+--------------+ LAST NAME FIRST NAME MIDDLE NAME

---------------------------------------------------------------+----------

SIGNATURE OF PERSON CONTRIBUTOR ALIASES HT. WT.

FINGERPRINTED AND ADDRESS (IN.)



DATE OF

----------------------------- BIRTH

RESIDENCE OF PERSON

FINGERPRINTED HAIR EYES



--------------------------------------------------------------------------

OCCUPATION ARREST NUMBERLEAVE THIS SPACE BLANK



------------------------------------------

SCARS AND MARKS PLACE OF

BIRTH 26 5 R OOO 12

-------------CLASS

-----------------------------CITIZENSHIP 12 W MOI

SIGNATURE OF OFFICIAL DATE

TAKING FINGERPRINTS CHECK IF

NO CRIMINALREF.

RECORD IS

DESIRED

---------------------------------------------------------------------------

1. RIGHT THUMB2. RIGHT INDEX3. RIGHT 4. RIGHT RING 5. RIGHT LITTLE

MIDDLE

26 12 0 17 12

[Illustration][Illustration][Illustration][Illustration][Illustration]

---------------------------------------------------------------------------

\ R W \ \

---------------------------------------------------------------------------

1. LEFT THUMB 2. LEFT INDEX 3. LEFT 4. LEFT RING 5. LEFT LITTLE

MIDDLE

I M 18 I 15

[Illustration][Illustration][Illustration][Illustration][Illustration]

---------------------------------------------------------------------------

W W / W /

---------------------------------------------------------------------------



The chart, figure 351, will illustrate the manner in which the ridge

counts are translated into the symbols I and O so they may be grouped

and sequenced with the whorl tracings I, M and O.



THE MAJOR DIVISION: The major division is placed just to the left of

the primary in the classification formula. Where whorls appear in the

thumbs the major division reflects the whorl tracings just as the

subsecondary does. For example, a major division of I over M in the

primary 5 over 17 would reflect an inner-traced whorl over a

meeting-traced whorl in the thumbs. Where loops appear in the thumbs,

however, a table is used to translate the ridge counts into the small,

medium, or large groups, designated by the letters S, M, L. An

expanding table is used for the right thumb when large-count loops

appear in the left thumb, as shown in the chart (fig. 351). This table

is used because it affords a more equitable distribution of prints as

a whole, for filing purposes within the groups indicated.







--RIGHT HAND--

---------------------------------------------------------------------------

R THUMB R INDEX R MIDDLE R RING R LITTLE

---------------------------------------------------------------------------

WHEN LEFT THUMB 1-9 = I 1-10 = I 1-13 = I

IS 16 OR LESS 10 AND OVER = O11 AND OVER = O14 AND OVER = O

1-11 = S

12-16 = M

17 AND OVER = L

--------------------RIDGE COUNT OF SECOND SUBSECONDARY---------------------

WHEN LEFT THUMB 1-5 = S 1-8 = S 1-10 = S

IS 17 OR OVER 6-12 = M 9-14 = M 11-18 = M

1-17 = S 13 AND OVER = L15 AND OVER = L19 AND OVER = L

19-22 = M

23 AND OVER = L

---------------------------------------------------------------------------



--LEFT HAND--

---------------------------------------------------------------------------

L THUMB L INDEX L MIDDLE L RING L LITTLE

---------------------------------------------------------------------------

1-11 = S

12-16 = M <------------------VALUES SAME AS ABOVE------------------->

17 AND OVER = L

---------------------------------------------------------------------------



Table for major divisions of loops:



Left thumb denominator Right thumb numerator



{ 1 to 11, inclusive, S (small).

1 to 11, inclusive, S (small) { 12 to 16, inclusive, M (medium).

{ 17 or more ridges, L (large).





{ 1 to 11, inclusive, S (small).

12 to 16, inclusive, M (medium) { 12 to 16, inclusive, M (medium).

{ 17 or more ridges, L (large).



{ 1 to 17, inclusive, S (small).

17 or more ridges, L (large) { 18 to 22, inclusive, M (medium).

{ 23 or more ridges, L (large).



The fingerprint card appearing in figure 352 shows a major division of

L over L, which is obtained by counting the ridges (24 in the right

thumb and 18 in the left thumb) which, according to the table, is

translated into L in both thumbs.



THE FINAL: It is, of course, desirable to have a definite sequence or

order of filing the prints within the subdivided groups. This order is

attained through the use of the final, which is based upon the ridge

count of the loop in the right little finger. It is indicated at the

extreme right of the numerator in the classification. Note figure 352.

If a loop does not appear in the right little finger, a loop in the

left little finger may be used. It is then indicated at the extreme

right of the denominator (fig. 353). If no loops appear in the little

fingers, a whorl may be used to obtain a final, counting from left

delta to core if in the right hand and from right delta to core if in

the left hand. If there are two or more cores (usually applies to

accidental whorls), the ridge count is made from left delta (right

hand) or right delta (left hand) to the core which is the least

number of ridges distant from that delta. An exception is made in the

case of the double loop. The double loop is counted from the delta to

the core of the upright loop. Where loops of a double loop are

horizontal, the nearest core is used. Should both little fingers be a

or t, no final is used. The use of a whorl in a little finger for a

final is required only in connection with a large group or collection

of prints, such as the 32 over 32 primary.







LEAVE THIS SPACE BLANK SEX

+--------------+

FBI No. RACE

+--------------+ LAST NAME FIRST NAME MIDDLE NAME

---------------------------------------------------------------+----------

SIGNATURE OF PERSON CONTRIBUTOR ALIASES HT. WT.

FINGERPRINTED AND ADDRESS (IN.)



DATE OF

----------------------------- BIRTH

RESIDENCE OF PERSON

FINGERPRINTED HAIR EYES



--------------------------------------------------------------------------

OCCUPATION ARREST NUMBERLEAVE THIS SPACE BLANK

LLL

------------------------------------------ LMM

SCARS AND MARKS PLACE OF

BIRTH 24 L I R O O O 17

-------------CLASS

-----------------------------CITIZENSHIP L I R O O O

SIGNATURE OF OFFICIAL DATE

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NO CRIMINALREF.

RECORD IS

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---------------------------------------------------------------------------

1. RIGHT 242. RIGHT 133. RIGHT 314. RIGHT 215. RIGHT 17

THUMB INDEX MIDDLE RING LITTLE



[Illustration][Illustration][Illustration][Illustration][Illustration]

---------------------------------------------------------------------------

\ R \ \ \

---------------------------------------------------------------------------

1. LEFT 182. LEFT 163. LEFT 134. LEFT 185. LEFT 20

THUMB INDEX MIDDLE RING LITTLE



[Illustration][Illustration][Illustration][Illustration][Illustration]

---------------------------------------------------------------------------

/ R / / /

---------------------------------------------------------------------------



THE KEY: The key is obtained by counting the ridges of the first loop

appearing on the fingerprint card (beginning with the right thumb),

exclusive of the little fingers which are never considered for the key

as they are reserved for the final. The key, no matter where found, is

always placed to the extreme left of the numerator of the

classification formula (fig. 353).





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