Fingerprinting: “E” Before “I” in This Handy Guide

Especially for you, an E-I guide to fingerprinting … and more.


Epidermis– Outer layer of the skin.

Epithelial Cells– Cells that line and protect the surfaces of the body. These cells form epithelial tissues such as skin and mucous membranes.

Exemplar– Fingerprints of an individual, whose identity is known or claimed, and is

deliberately recorded.


FER– Fluorescence Excitation Radiometry.

FFS– Fellow of The Fingerprint Society.

Final– Numerical value typically derived from the ridge count of the right little finger.

Fingerprint Powders– Powders used to develop and visualize friction ridge detail.

The Flak-Conley Classification System– A fingerprint classification system developed in 1906, in New Jersey.

Flats– An unofficial term for the intentional recording/fingerprinting of the four fingers of either hand, taken simultaneously

Fluorescein– Fluorescent reagent used to enhance develop bloody friction ridge detail.

Folien– A gel used to lift and preserve latent fingerprints.

Friction Ridge– The raised portion of skin found on the palmar and plantar skin.

Identical twins do not share the same fingerprints.


GYRO– The color-coded system of documenting the level of confidence that a fingerprint examiner assigns to various print details observed during the examination and comparison of prints. GYRO is an acronym for Green / Yellow / Red / Orange.

  • Green is used to note ridge details observed with high confidence levels.
  • Yellow = medium confidence levels (detail with negligible alteration).
  • Red = a great deal of uncertainty (details of great distortion).
  • Orange notes ridge details discovered after the initial examination.

Gentian Violet (akaCrystal Violet) – a violet stain used to develop and/or enrich friction ridge detail. Crystal Violet dyes the fats and oils found in sebaceous sweat. This stain is typically used to develop prints on the adhesive side of tape.

Grip Print– Prints left behind after a person “grips” an object. The entire print typically includes the side of the index finger, the inner side of the interdigital areas, the web area, and the inner side of the thumb.


Hallux– Big toe.

Huffing/The Hot Breath Technique– Breathing on a latent print introduces humidity into an older (latent/invisible) fingerprint. Doing so helps the investigator visualize it.

Hungarian Red– A red stain used to develop bloody friction ridge detail.

Hyperdactyly– Having more than the normal number of fingers or toes.

Hyperhidrosis– Medical condition that increases perspiration.

Hypohidrosis– Medical condition that reduces sweating.


IAFIS– Integrated Automated Fingerprint Identification System.

Image Reversal– An Image Reversal typically occurs in unintentional transferred prints (placing evidence seized in one case on top of evidence from another, such as plastic bags containing narcotics).

FYI Writers – When friction ridges from a latent print are reversed (planting a fingerprint at a crime scene, or accidentally) they tend to appear very thin and thready. Also, the background area surrounding the “new” print may not match the surface of the place where the transferred print was left. The background pattern could/would transfer along with the print. It’s also important to note that these prints are obvious mirror images and would be easily recognized by a skilled examiner.


Immigration Delay Disease (IDD)– A rare congenital absence of fingerprints. To learn more, click here.

Iodine– As either a vapor or solution, this substance helps to visualize friction ridge detail by binding with fats and oils.


1 reply
  1. Jennifer Cornell
    Jennifer Cornell says:

    I really appreciate all of this information. Thank you for your help for all of us pen pushers out here!

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