IAI CLPE key terms

Hairless skin on the palmar and plantar surfaces whose epidermis carries raised ridges separated by furrows; its ridge pattern is unique and permanent, making it the anatomical basis for latent print comparison.

The overall ridge flow and pattern configuration of a print, such as a loop, whorl, or arch, visible without close inspection and used to include or exclude candidates before finer comparison.

Individual ridge path features including ridge endings, bifurcations, dots, and short ridges, along with their spatial relationships; this is the primary basis for most identification conclusions.

Fine ridge attributes such as pore position, ridge edge contour, incipient ridges, and ridge width, used to support or refine decisions in close comparisons or partial prints.

Specific points where a ridge ends, divides, or forms a distinctive shape; examiners count and map them to evaluate whether two impressions share a sufficiently rare arrangement.

A minutia where a single friction ridge terminates abruptly rather than continuing along its path; its location and orientation are recorded during comparison.

A minutia where one friction ridge splits into two diverging ridges; the fork point and the direction of the branches are mapped when comparing impressions.

The ridge area where three systems of ridges converge, forming a roughly triangular configuration; its position helps classify patterns and orient the print for comparison.

The innermost point or area of a pattern, located near the center of a loop or whorl; it anchors orientation and is used in classification rules.

Assigning a print to a category such as arch, loop, or whorl, with subtypes, based on ridge flow and delta/core relationships, to support filing and initial screening.

The study of friction ridge skin morphology and its variation, including edge shapes, pores, and incipient ridges, applied when detail beyond minutiae is needed.

An opening of a sweat gland duct on the crest of a friction ridge; its position and spacing can support comparison when ridge edges are well recorded.

A narrow channel carrying eccrine sweat from the gland to a pore on the ridge surface; its openings contribute to the residue that forms latent prints.

A short, shallow ridge that develops between fully formed ridges and appears as a fragmentary line; its presence and position can aid fine-detail comparison.

Permanent irregular skin damage that disrupts ridge flow on a finger; a scar can be a highly distinctive feature if it is clearly recorded in both impressions.

A known print taken under controlled conditions from a known person, used as the reference for comparison against a latent impression.

An impression of friction ridge skin left on a surface by transferred residue, usually invisible to the eye, that must be developed and then compared with known prints.

An impression of established origin, such as a ten-print card or inked/palm print, whose ridge detail is compared with a questioned latent impression.

A structured comparison method: Analysis of the questioned and known prints, Comparison of their features, Evaluation of similarities and differences, and Verification by another qualified examiner.

The first ACE-V phase, in which an examiner assesses the clarity, distortion, and usable detail of each impression and decides whether comparison is feasible.

The ACE-V phase in which the examiner weighs the significance of similarities and differences and reaches a conclusion such as identification, exclusion, or inconclusive.

Independent review of a comparison by another qualified examiner, typically without knowledge of the first conclusion, to confirm or challenge the result.

A verification in which the reviewer is not told the original examiner's conclusion, reducing bias from knowing the expected answer.

A conclusion that two impressions came from the same friction ridge skin, based on agreement of unique features in sufficient quantity and quality.

A conclusion that two impressions did not come from the same skin area, justified by an unexplainable difference in ridge detail.

A conclusion that the available detail is insufficient to support identification or exclusion, often because of distortion, partial area, or poor quality.

A judgment that a latent impression has enough clear, reliable ridge detail to be compared meaningfully; unsuitable prints may be documented but not compared.

Change in the appearance of a print caused by pressure, movement, surface curvature, or application method, which can alter ridge spacing and minutiae positions.

Ridge deformation caused by uneven or excessive force during contact, producing stretched, compressed, or smeared areas that complicate feature matching.

A tendency for expectations or case information to influence an examiner's perception and judgment; procedures such as blind verification and linear review are used to limit it.

A workflow that reveals case information to examiners in stages, after initial observations are documented, to reduce the influence of extraneous context on conclusions.

Any physical or chemical process that makes an invisible latent print visible, such as powdering, fuming, or reagent treatment, chosen to suit the surface and residue.

Applying fine powder with a brush or applicator so particles adhere to the residue of a latent print on a nonporous surface, revealing ridge detail for photography or lifting.

Exposing an item to vaporized cyanoacrylate ester in a closed chamber so a white polymer deposits on print residue, making it visible on many nonporous surfaces.

A chemical reagent applied to porous items such as paper that reacts with amino acids in print residue to produce a purple color, often after heat and humidity treatment.

A fluorogenic reagent for porous surfaces that reacts with amino acids and fluoresces under appropriate light, often giving stronger sensitivity than ninhydrin when imaged correctly.

The common working name for cyanoacrylate fuming, in which heated glue vapor coats latent residue on nonporous items with a durable white deposit.

A high-vacuum process that evaporates gold and then zinc onto items, forming a thin metal film that reveals latent prints on difficult nonporous surfaces such as plastic bags.

Adhesive tape applied over a developed print on a nonporous surface to transfer the powder image to a backing card for preservation and later comparison.

Documenting a latent print with a camera before or instead of lifting, using appropriate lighting, scale, and focus so ridge detail remains suitable for comparison.

A lamp or laser emitting specific wavelengths, often with filters, used to make prints or treated prints fluoresce or to increase contrast on a surface.

A type of sweat gland most numerous on friction ridge skin; its watery secretion forms much of the residue examined in latent print development.

A type of gland associated with hair follicles that secretes oily material; transferred sebum on fingers contributes significantly to latent print residue.

A material such as paper or untreated wood that absorbs print residue, requiring reagent-based development rather than powder dusting.

A material such as glass, metal, or plastic that does not absorb residue, so prints remain on the surface and can be powdered, fumed, or lifted.

A documented record of every person who handled evidence and when, from collection through analysis and storage, supporting integrity and admissibility.

Selecting containers and handling methods that protect prints from damage, contamination, and loss, such as paper bags for porous items and rigid containers for fragile objects.

Introduction of foreign material or prints onto evidence, or transfer between items, that can create misleading impressions; controlled handling and clean tools reduce it.

Planned activities such as audits, proficiency testing, and documented procedures that ensure laboratory work meets defined standards and remains reliable.

Routine checks performed during work, such as reagent testing or equipment calibration, to confirm that processes are performing within acceptable limits.

A written, approved instruction describing how a task is performed, including materials, steps, and acceptance criteria, so work is consistent and defensible.

Examination of casework, reports, and conclusions by a qualified peer to confirm that methods, documentation, and interpretations meet laboratory requirements.

Periodic testing of examiners with known-answer or declared-value samples to demonstrate competence and reveal training needs.

Contemporaneous records of observations, methods, and decisions made during examination, forming the basis for reports and for later review or testimony.