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Extensions to Henry Fingerprint System: WCDX & Special Loops

Extensions of Henry Fingerprint System WCDX & Special Loops

Extension to Henry’s fingerprint system is quite a viable way to come up with smaller groups for comparisons. Fingerprint classification extensions are used by various federal agencies to downsize the larger groups making classification systems more efficient and less time-consuming.

To meet the efficiency of searching prints in larger groups databases, many federal agencies come with extensions to further classify Henry’s six divisions system. 

In this post, I listed down three extensions that are used by the FBI for their Henry classification system. These are

  1. WCDX classification
  2. Special Loops extension 
  3. Second sub secondary classification

WCDX Classification of Fingerprint

what is WCDX Classification of Fingerprint

WCDX is an acronym for Whorl, Central Pocket, Double, and Accidental loop whorls. It is a special extension majorly used to classify the large groups of whorls patterns such as 32/32. 

In this classification, only whorls are classified and named down based on the pattern appearing on all of the fingers.

Rules for WCDX Extension to Henry Classification

Value for W.C.D.X. Classification of Fingerprint

As stated earlier, this special extension is used by the FBI for 10 digits that have large whorl groups.

But why only for large whorl groups?

Because, as per the FBI fingerprint database, there are two large primary groups (31/32 and 32/32) of whorls that share a good percentage of 10-digits.

Even after categorizing 32/32 (or 31/32) in Henry’s six divisions, it still has a larger search group size (in millions) that makes comparison impractical.

That’s why they are further subdivided using extensions. 

A. Values For Index Finger

For index fingers, capital letters are used as their value.

Finger TypePatternsWCDX Value
Index FingersPlain WhorlW
 Central Pocket Loop WhorlC
 Double Loop whorlD
 Accidental loop whorlX

B. Values for All Fingers Except Index

For fingers other than Index, small letter values of different types of whorls are used.

Finger TypesPatternsWCDX Value
Fingers except, IndexPlain Whorlw
 Central Pocket Loop Whorlc
 Double Loop whorld
 Accidental loop whorlx

Calculation for WCDX Classification Value

With the help of the following extracted data from a 10 digit card, let’s find out the WCDX value.

how to calculate WCDX Classification Value

Wonder! why all the markings are in ‘O’, ‘M’, and ‘I’? Check the rules on how to fill 10 digits fingerprint card (coming soon).

Step 1: Finding Henry Classification Value

I created a dedicated article on how you calculate the values of all six Henry classification systems in no time.

KeyMajorPrimarySecondarySubSecondaryFinal
omittedO32WIMO17
 I32WOMI 

Step 2: Evaluating WCDX Value

Rt ThumbRt IndexRt MiddleRt RingRt Little
wCdwc
Lt ThumbLt IndexLt MiddleLt RingLt Little
cWwwx

Note: Instead of writing ‘ww’, the numerical value of their consecutive occurrence is used. So, it will be written as ‘2w’.

Step 3: Reperesentation of WCDX in Henry Line

This is how WCDX classification rests on Henry’s line.

representation of WCDX classification on henry line

Practice Set #1 For WCDX Extension

example of wcdx extension of fingerprint

Step 1: Finding Henry Classification Value

KeyMajorPrimarySecondarySubSecondaryFinal
omittedI32WIMM17
 M32WOOI 

Step 2: Evaluating WCDX Value

Rt ThumbRt IndexRt MiddleRt RingRt Little
wCdxw
Lt ThumbLt IndexLt MiddleLt RingLt Little
cDxwx

Step 3: Representation of WCDX in Henry Line

This is how WCDX classification rests on Henry’s line.

Practice #2 for WCDX in Henry Line

Special Loop Extension of Fingerprint

what is Special Loop Extension of Fingerprint

It is used for further classifying 10-digits with all loop patterns— Henry’s primary groups such as 1/1 with all loops. The value of the special loop extension is brought by ridge count values of the index, middle and ring finger (sometimes left little finger) of both hands.

The primary group 1/1 accounts for 25% of the total prints filled by the FBI.

Rules of Using Special Loop Classification

  • Fingers Used: Index, middle, and ring finger (sometimes left little finger)
  • Numerator: Right-hand fingers
  • Denominator: Left-hand fingers
  • Position: Above the values of sub secondary classification
  • Patterns: Loops
  • Values: Specific numeral based on ridge counts
  • Applicable: Primary group 1/1 that has all loop patterns

Value for Special Loop Extension of Fingerprint

The following are the values that are assigned based on the ridge counts in the index, middle, and ring fingers.

Ridge CountSpecial Loop Value
1 to 41
5 to 82
9 to 123
13 to 164
17 to 205
21 to 246
25 and more7

How to Calculate Special Loop Extension’s Value?

With the following 10 digits card information, let find out the value of the special loop extension.

How to Calculate Special Loop Extension Value

Step 1: Calculating Henry Classification Number

KeyMajorPrimarySecondarySubSecondaryFinal
9S1UOII12
 S1RIOI 

You can check the dedicated article on how you come up with the Henry classification number like above. 

Step 2: Finding Special Loop Extension Value

Right Hand Loop Counts

  • Index= 11= 3 (9 to 12= 3 special loop value)
  • Middle= 10= 3
  • Ring= 12= 3

Left Hand Loop Counts

  • Index= 9= 3 (9 to 12= 3 special loop value)
  • Middle= 12= 3
  • Ring= 12= 3

Step 3: Representation of Special Extension in Henry Line

This is how special loop extensions classification is placed in Henry’s classification line.

Representation of Special Extension in Henry Line

Practice #1 For Special Loop Extension

Practice #1 For Special Loop Extension

Step 1: Calculating Henry Classification Number

KeyMajorPrimarySecondarySubSecondaryFinal
15S1UOOO16
 L1ROOO 

Step 2: Finding Special Loop Extension Value

Right Hand Loop Counts

  • Index= 11= 4 (13 to 16= 4, special loop value)
  • Middle= 10= 4
  • Ring= 12= 5 (17 to 20= 5, special loop value)

Left Hand Loop Counts

  • Index= 9= 4 (13 to 16= 4, special loop value)
  • Middle= 12= 4
  • Ring= 12= 4

Step 3: Representation of Special Extension in Henry Line

Special loop value Extension in Henry Line

Second Sub Secondary Classification of Fingerprint

Second Subsecondary classification is majorly used for classifying groups that are too large. You can check the dedicated article on how to calculate secondary sub secondary classification values

Other General Categorization in Henry Fingerprint System by FBI

For ease during analysis, various ‘reference’ pointers are brought by federal bureaus. These reference categorizing points may be age, gender, dead, and presumptive dead.

Apart from these, amputated and scarred fingers are commonly categorized criteria as references.

In the case of amputated fingers, the reference is given by “AMP”, this is how it looks.

For permanently scarred fingers, the references are divided into 3 groups;

  • right hand,
  • left hand, and
  • both hands

Similarly, for mutilated fingerprints, a separate reference is categorized in employed.

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