Desktop version

Home arrow Law

  • Increase font
  • Decrease font

<<   CONTENTS   >>

II: Development, Identification, and Presentation of Fingerprints

Known/Direct/Inked Fingerprints: Processing Techniques for Unknown/Latent Fingerprints


Known Fingerprints

Whether the method of taking inked prints is manual or through the use of a live scan, the process of obtaining good quality prints is basically the same. Taking a good quality fingerprint from a known source that can be used at a later time for a variety of purposes, from searching to individualization, is the ultimate goal. The terms known, direct, and inked are considered synonymous. Simply stated, these are prints taken from a known source. The clarity of the prints should be sufficient to allow for the comparison process to be conducted. These prints may also be known as tenprint cards.

Manual Method

I. Equipment required for taking known fingerprints (Figure 5.1)

A. Inking Plate: Hard, rigid, scratch-resistant surface; glass, metal, or scratch-resistant plastic

  • 1. The inking plate should be affixed to a wood or other solid frame to prevent breakage.
  • 2. The inking plate should be elevated to a height to allow the subject’s arm/hand to assume a horizontal position.
Manual fingerprint equipment

Figure 5.1 Manual fingerprint equipment.

Manual fingerprint methodology

Figure 5.2 Manual fingerprint methodology.

B. Cardholder: Used to hold the card flat and maintain an appropriate surface for registering required fingerprint information.

C. Printer’s Ink: Required to provide the necessary transfer medium to obtain proper finger and/or palm prints. Printer’s ink is used due to its quick-drying properties, ease of use, and permanence.

Manual fingerprint technique (rolling prints)

Figure 5.3 Manual fingerprint technique (rolling prints).

Manual fingerprint technique (rolling prints)

Figure 5.4 Manual fingerprint technique (rolling prints).

D. Roller: Preferably 6 inches long by 2 inches in diameter. Used to provide a uniform layer of ink onto the inking plate. The ink film must be sufficient to provide a transfer medium, but not too much to prevent proper inking of fingerprints.

E. Fingerprint Card: Standard 8x8 inch identification card

Manual fingerprints (flat impressions)

Figure 5.5 Manual fingerprints (flat impressions).

Manual (flat impression)

Figure 5.6 Manual (flat impression).

  • 1. Upper ten fingerprint impressions are taken separately and rolled.
  • 2. Lower impressions are taken simultaneously and are known as plain or flat impressions. Fingers are not rolled. The four fingers of each hand are taken; then thumbs are separately printed.

II. Preparation

A. Inking the plate

  • 1. Place a small daub of ink on the plate and use a roller to smoothen ink onto the surface, ensuring the entire plate is covered with a thin film of ink.
  • 2. Test the amount visually and with your finger. The film should appear almost transparent.

III. Taking the fingerprints (Figures 5.2 through 5.6)

A. The subject should stand in front of and at the forearm’s length from the inking plate.

B. The person taking the prints should stand slightly to the left of the subject when printing the right hand, and slightly to the right when printing the left hand.

C. The side of the bulb of the finger is placed on the inking plate and the finger is rolled to the other side until it is entirely covered with ink. The entire bulb should be covered with ink from the tip to below the first joint.

Recording fingerprints with coroner’s spoon.

D. The subject should be cautioned to relax and refrain from trying to help the operator. Oddly enough, the more the subject tries to help, usually the worse the prints will be.

1. Advise the subject to relax and “look at some distant object.”

E. Rolled impressions (Figures 5.2 through 5.6)

  • 1. Press the finger lightly on the card and roll from side to side, transferring the ink to the card (roll from cuticle to cuticle).
  • 2. The hand should be rolled from the awkward to the easy position.

a. The fingers should be rolled away from the center of the body.

b. The thumbs should be rolled toward the center of the body.

F. Plain impressions (simultaneously lay down four fingers on each hand; Figure 5.6)

1. All fingers should be inked at the same time and pressed onto the card simultaneously. If all four fingers will not fit in the box, then print three fingers and place the fourth on the rear of the card, making note of this on the face of the card.

a. Before inking the subject, advise the subject to extend their four fingers and hold in that position. Be careful, as some subjects may have a bow to their fingers. If that is the case, advise subjects they are extending too tightly.

2. The thumbs are then inked individually and taken separately. Remember to press down; do not roll the thumbs.

G. Taking of palm prints

  • 1. The palm needs to be inked completely. This means the inking roller should be rolled over the entire palm (from fingertips to bottom of palm). The palm is then pressed onto the card. The palm is not rolled. The operator taking the palm print should ensure there is sufficient pressure to record the entire palm, but not too much pressure on the palm, which would cause a smearing effect.
  • 2. The side of the hand (palm) then needs to be inked to record the area known as the writer’s palm. Following the procedures mentioned previously, the operator again needs to place the palm onto the card to properly record sufficient information from the side of the palm remembering not to press too hard or move the palm and thereby cause smearing.

IV. Problems in taking fingerprints

A. Mechanical operation:

1. Poor impressions are usually caused by

a. Poor, thin ink

b. Failure to clean the inking apparatus and finger prior to printing

i. Alcohol or other commercial preparation may be used.

ii. Perspiring fingers should be wiped dry (perspiring fingers will cause smeared fingerprints).

c. Failure to completely roll the fingers fully from one side to the other and to ink the whole area from tip to below the first joint

d. Using too much ink

e. Insufficient inking

f. Allowing the fingers to slope or twist resulting in smears and blurs (Note: One of the biggest challenges is to take proper control of the subject being printed.)

B. Temporary disabilities

  • 1. Fresh cuts or wounds
  • 2. Bandaged finger or fingers
  • 3. Occupational issues: Bricklayers, carpenters, secretaries, dishwashers

a. Try using a small amount of ink

b. Might also try using softening agents (oils/creams)

4. Excessive perspiration

a. Wash hands or wipe with alcohol.

5. Young children with small ridges. As children get older, the ridges become more pronounced and recording becomes much easier. Generally, children younger than three years old will not leave good prints.

C. Permanent disabilities

1. Lack of fingers

a. Note on the card: “Missing at birth.”

b. Note on the card: “Amputated on_.”

c. If part of the first joint is present, print it.

d. If all fingers are missing, print the feet.

2. Crippled or deformed fingers and hands.

a. If fingers are so deformed that they are touching the palm permanently, note on the card.

b. In other cases, use spatula, small holder, or curved holder (coroner’s spoon).

c. For fingers of elderly individuals with faint ridges, use a very small amount of ink.

D. Deformed fingers

Automated fingerprint equipment (live scan)

Figure 5.7 Automated fingerprint equipment (live scan).

  • 1. If the subject has more than ten fingers, print the thumb and the next four fingers on the front of the card. Print the remaining fingers on the back of the card. Make note of this on the face of the card.
  • 2. If the subject has webbed fingers, roll as completely as possible and make notation on the card.
  • 3. Split thumbs are classified as if the joint toward the outside of the hand were not present.

Note: Where fingerprints on the rolled impressions are not of sufficient clarity to read or to be scanned into a database, those fingers may use a “Tab Over.” The tab over is an adhesive-backed, square tab that may be used to do a reprint of the finger in question. The tab over is placed in the square of the fingerprint to be retaken. There is a caution that must be advised: no more than two tab

Automated fingerprint equipment (live scan)

Figure 5.8 Automated fingerprint equipment (live scan).

Live scan fingerprints

Figure 5.9 Live scan fingerprints.

Live scan palm prints

Figure 5.10 Live scan palm prints.

overs may be used on a card or that card will be rejected by the FBI or other agency that will be registering or searching that card in a database.

Live Scan (Figures 5.7 through 5.10)

Live scan prints are basically taken in the same manner as manual fingerprints. However, slightly different protocols must be followed to ensure the quality of the known fingerprint.

With the manual method, proper inking of the prints is accomplished by ensuring the equipment is clean and in order. Live scans must adhere to the same basic principles. With live scans, after a specified number of uses, depending on the system, the system must be checked or recalibrated for accuracy. The printer that is used with the system must also be checked for accuracy to ensure that a quality product is generated. The live scan system automatically records the prints, so the need for extreme accuracy is paramount. Live scan, as the name implies, displays an image on a monitor to the fingerprint operator to register for printing. The main difference between obtaining a live scan print and a manual print is that the live scan print cannot be rolled in the same manner as an inked print. The reader on the live scan system is flat, and therefore the print operator must place the finger on the reader and apply pressure to spread the bulb of the finger onto the reader. Too much pressure and the print becomes smeared. Too little pressure and the entire print will not be captured on the reader. An advantage of the live scan system is that if the operator does not like the print that was registered, that print can be eliminated and retaken before permanent registration onto the fingerprint card. The flat impressions at the bottom of the card are taken in the same fashion as in the manual method. Four fingers are simultaneously taken, then the thumbs. Live scan is considered to be more efficient than the manual method. From personal experience, the author can state that the live scan system is not as messy as the manual method. Both systems share the same challenges and issues when it comes to poor-quality prints and the reasons for obtaining them. As with everything in life, both systems have their advantages and disadvantages. That topic is material for a different discussion.

Unknown Fingerprints

<<   CONTENTS   >>

Related topics