ASTM E1732-24

Standard Terminology Relating to Forensic Science

SIGNIFICANCE AND USE
3.1 These terms have application to forensic practice.  
3.1.1 For ASTM International standards, the standard designation is followed by a dash and a two-digit year designation in bold type, for example, E2161 - 19. The year citation references the year of publication of the standard from which the entry is taken, not necessarily the current year of publication of the standard.  
3.1.2 Citations from other than ASTM International standards may include an abbreviation and the standard number followed by a four-digit year designation in bold type, for example, ISO 9000:2015. The year citation references the year of publication of the standard from which the entry is taken. Such standards may also be referenced by a name followed by a year designation, for example, IUPAC Gold Book 2020 (1).5 Abbreviations are detailed under, “All terms sourced from other standards than Committee E30 standards are listed in Section 2.”  
3.1.3 For entries followed simply by a reference, for example, ISO 9000:2015 or E456 - 17, the reader can assume that the entry is accurately copied from the reference with no modifications except for ASTM International format conventions. For entries that are slightly modified versions of something from a known source, reference citations read, “Based upon definition by…” Following the “by” is the source name and year that the entry was taken or modified. The boldface numbers in parentheses refer to a list of references at the end of the terminology.  
3.1.4 For entries from textbooks, a reference following the entry has the name or title of the text, author(s), edition (if applicable), and the year of publication or copyright.  
3.1.5 An entry could have a definition of a term with one reference, and the discussion following the definition has a different reference.  
3.1.6 Citations from Merriam-Webster’s Online Dictionary (2) include the date retrieved from the online dictionary and the URL of the cited term and definition.  
3.1.7 Each defin...
SCOPE
1.1 This terminology is the compilation of all terms used by Committee E30 on Forensic Sciences.  
1.1.1 This terminology consists mostly of definitions that are specific to forensic science and forensic practice. Meanings of the same terms used outside of forensic practice can be found in other compilations or dictionaries of general usage.  
1.1.2 The specific E30 subcommittee (SC) that has responsibility for each term is the first attribution noted, in square brackets, after the definition. The designation of the standard(s) in which the terms appear is given after the subcommittee. The wording of an entry cannot be changed without approval per the Committee E30 Bylaws. Users of this compilation should also review any SC terminology standard for more details or interpretations of these terms and their use by the SC.  
1.2 This terminology is a tool for managing the committee’s terminology. This includes finding, eliminating, and preventing redundancies in which two or more terms relating the same concept are defined in different words.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Jan-2024
• ICS: 01.040.11 - Health care technology (Vocabularies)
• ICS: 11.020 - Medical sciences and health care facilities in general
• Technical Committee: E30 - Forensic Sciences
• Drafting Committee: E30.92 - Terminology

Relations

• Replaces: ASTM E1732-22 - Standard Terminology Relating to Forensic Science
• Effective Date: 01-Feb-2024
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM E456-13a(2022) - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM E2154-15a - Standard Practice for Separation and Concentration of Ignitable Liquid Residues from Fire Debris Samples by Passive Headspace Concentration with Solid Phase Microextraction (SPME) (Withdrawn 2024)
• Effective Date: 01-Sep-2015
• Referred By: ASTM E1969-19 - Standard Practice for Microcrystal Testing in Forensic Analysis for Methamphetamine and Amphetamine
• Effective Date: 01-Feb-2024
• Referred By: ASTM E3329-21e1 - Standard Practice for Establishing an Examination Scheme for Explosive Residues
• Effective Date: 01-Feb-2024
• Referred By: ASTM E1388-24 - Standard Practice for Static Headspace Sampling of Vapors from Fire Debris Samples
• Effective Date: 01-Feb-2024
• Referred By: ASTM E860-22 - Standard Practice for Examining and Preparing Items That Are or May Become Involved in Criminal or Civil Litigation
• Effective Date: 01-Feb-2024
• Referred By: ASTM E2708-23 - Standard Terminology for Accreditation and Certification
• Effective Date: 01-Feb-2024
• Referred By: ASTM E3245-20e1 - Standard Guide for Systematic Approach to the Extraction, Analysis, and Classification of Ignitable Liquids and Ignitable Liquid Residues in Fire Debris Samples
• Effective Date: 01-Feb-2024
• Referred By: ASTM E3309-21 - Standard Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry (SEM/EDS)
• Effective Date: 01-Feb-2024
• Referred By: ASTM E3260-21 - Standard Guide for Forensic Examination and Comparison of Pressure Sensitive Tapes
• Effective Date: 01-Feb-2024
• Referred By: ASTM E3392-24 - Standard Guide for Forensic Physical Fit Examination
• Effective Date: 01-Feb-2024
• Referred By: ASTM E3189-19 - Standard Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Static Headspace Concentration onto an Adsorbent Tube
• Effective Date: 01-Feb-2024
• Referred By: ASTM E1968-19 - Standard Practice for Microcrystal Testing in Forensic Analysis for Cocaine
• Effective Date: 01-Feb-2024

Overview

ASTM E1732-24: Standard Terminology Relating to Forensic Science is a comprehensive terminology standard developed by ASTM International. Prepared by Committee E30 on Forensic Sciences, this document consolidates definitions of terms that are widely used in forensic science and forensic practice. The standard aims to harmonize language and terminology across various subfields of forensics, supporting clear communication, consistency, and the elimination of redundancy.

The terminology covers both general forensic science concepts and specialized terms relevant to criminalistics, digital and multimedia evidence, questioned documents, and interdisciplinary forensic applications. By referencing established terms from related ASTM standards and international sources such as ISO and IUPAC, ASTM E1732-24 ensures authoritative, up-to-date definitions for practitioners.

Key Topics

• General Forensic Science Terms: Core terminology applicable across multiple disciplines in forensic science, curated by the E30.92 Terminology Subcommittee.
• Criminalistics: Specialized terms for seized drug analysis, gunshot residue analysis, fire debris, paint, glass, textiles, and other trace evidence, maintained by E30.01.
• Digital and Multimedia Evidence: Terms relating to computer forensics, digital imaging, facial identification, and magnetic card examination, curated by E30.12.
• Interdisciplinary Forensics: Terminology addressing cross-disciplinary forensic practices, managed by E30.11.
• Questioned Documents: Vocabulary specific to the analysis of documents in forensic contexts.
• Attribution and Referencing: Each term specifies attribution to its responsible subcommittee, references to relevant standards, and source acknowledgments when definitions are based on external documents or standards.
• Consistency and Redundancy Elimination: The standard facilitates identification and removal of redundant or conflicting definitions, ensuring uniformity across forensic science literature.

Applications

ASTM E1732-24 serves as the foundational reference for:

• Forensic Laboratories and Practitioners: Standardized terminology enhances the consistency of reports, testimony, quality assurance documentation, and inter-laboratory communications.
• Legal and Regulatory Compliance: Lawyers, judges, and policymakers can rely on the standard to clarify terms used in expert reports, court proceedings, and forensic contracts, improving legal clarity.
• Education and Training: Academic institutions and professional development programs use ASTM E1732-24 as a reference in curriculum design, training modules, and certification exams.
• Method Validation and Quality Systems: The terminology supports clarity in method validation, proficiency testing, and performance audits by offering precise definitions referenced in other forensic standards.
• Standard Development: Forensic science committees and working groups consult ASTM E1732-24 to ensure new protocols and methods do not introduce conflicting or redundant terminology.

Related Standards

ASTM E1732-24 references and aligns with several key standards, including:

• ASTM E2161: Terminology Relating to Performance Validation in Thermal Analysis and Rheology
• ASTM E177, E456: Terminology for Precision, Bias, Quality, and Statistics
• ASTM E2916: Terminology for Digital and Multimedia Evidence Examination
• ISO 9000: Quality Management Systems-Fundamentals and Vocabulary
• ISO 21043-1: Forensic Sciences-Terms and Definitions
• ANSI/NIST-ITL 1: Data Format for Interchange of Biometric Information

These referenced documents, along with other ASTM and international standards, provide expanded technical foundations and maintain compatibility across global forensic science practices.

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Leverage ASTM E1732-24 to ensure your forensic documentation, communications, and training are built upon precise, internationally recognized terminology crucial for reliability and professionalism in forensic science.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1732 − 24
Standard Terminology
Relating to Forensic Science
This standard is issued under the fixed designation E1732; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
1.1 This terminology is the compilation of all terms used by
E456 Terminology Relating to Quality and Statistics
Committee E30 on Forensic Sciences.
E860 Practice for Examining and Preparing Items That Are
1.1.1 This terminology consists mostly of definitions that
or May Become Involved in Criminal or Civil Litigation
are specific to forensic science and forensic practice. Meanings
E1187 Terminology Relating to Conformity Assessment
of the same terms used outside of forensic practice can be
(Withdrawn 2006)
found in other compilations or dictionaries of general usage.
E1301 Guide for Proficiency Testing by Interlaboratory
1.1.2 The specific E30 subcommittee (SC) that has respon-
Comparisons (Withdrawn 2012)
sibility for each term is the first attribution noted, in square
E1388 Practice for Static Headspace Sampling of Vapors
brackets, after the definition. The designation of the standard(s)
from Fire Debris Samples
in which the terms appear is given after the subcommittee. The
E1412 Practice for Separation of Ignitable Liquid Residues
wording of an entry cannot be changed without approval per
from Fire Debris Samples by Passive Headspace Concen-
the Committee E30 Bylaws. Users of this compilation should
tration with Activated Charcoal
also review any SC terminology standard for more details or
E1413 Practice for Separation of Ignitable Liquid Residues
interpretations of these terms and their use by the SC.
from Fire Debris Samples by Dynamic Headspace Con-
1.2 This terminology is a tool for managing the committee’s
centration onto an Adsorbent Tube
terminology. This includes finding, eliminating, and preventing
E1588 Practice for Gunshot Residue Analysis by Scanning
redundancies in which two or more terms relating the same
Electron Microscopy/Energy Dispersive X-Ray Spectrom-
concept are defined in different words.
etry
1.3 This standard does not purport to address all of the
E1610 Guide for Forensic Paint Analysis and Comparison
safety concerns, if any, associated with its use. It is the E1618 Test Method for Ignitable Liquid Residues in Extracts
responsibility of the user of this standard to establish appro- from Fire Debris Samples by Gas Chromatography-Mass
priate safety, health, and environmental practices and deter-
Spectrometry
mine the applicability of regulatory limitations prior to use. E1968 Practice for Microcrystal Testing in Forensic Analy-
1.4 This international standard was developed in accor-
sis for Cocaine
dance with internationally recognized principles on standard- E1969 Practice for Microcrystal Testing in Forensic Analy-
ization established in the Decision on Principles for the
sis for Methamphetamine and Amphetamine
Development of International Standards, Guides and Recom- E2125 Practice for Microcrystal Testing in Forensic Analy-
mendations issued by the World Trade Organization Technical
sis for Phencyclidine and Its Analogues
Barriers to Trade (TBT) Committee. E2154 Practice for Separation and Concentration of Ignit-
able Liquid Residues from Fire Debris Samples by Pas-
2. Referenced Documents
sive Headspace Concentration with Solid Phase Microex-
2.1 ASTM Standards: traction (SPME)
E131 Terminology Relating to Molecular Spectroscopy E2161 Terminology Relating to Performance Validation in
Thermal Analysis and Rheology
E2224 Guide for Forensic Analysis of Fibers by Infrared
This terminology is under the jurisdiction of ASTM Committee E30 on
Forensic Sciences and is the direct responsibility of Subcommittee E30.92 on Spectroscopy
Terminology.
E2225 Guide for Forensic Examination of Fabrics and Cord-
Current edition approved Feb. 1, 2024. Published March 2024. Originally
age
approved in 1995. Last previous edition approved in 2022 as E1732 – 22. DOI:
E2227 Guide for Forensic Examination of Dyes in Textile
10.1520/E1732-24.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1732 − 24
Fibers by Thin-Layer Chromatography E3272 Guide for Collection of Soils and Other Geological
E2228 Guide for Microscopical Examination of Textile Fi- Evidence for Criminal Forensic Applications
E3294 Guide for Forensic Analysis of Geological Materials
bers
by Powder X-Ray Diffraction
E2363 Terminology Relating to Manufacturing of Pharma-
E3295 Guide for Using Micro X-Ray Fluorescence (μ-XRF)
ceutical and Biopharmaceutical Products in the Pharma-
in Forensic Polymer Examinations
ceutical and Biopharmaceutical Industry
E3296 Guide for Using Pyrolysis Gas Chromatography and
E2388 Guide for Minimum Training Requirements for Fo-
Pyrolysis Gas Chromatography-Mass Spectrometry in
rensic Document Examiners (Withdrawn 2020)
Forensic Polymer Examinations
E2678 Guide for Education and Training in Computer Fo-
E3309 Guide for Reporting of Forensic Primer Gunshot
rensics (Withdrawn 2023)
Residue (pGSR) Analysis by Scanning Electron
E2808 Guide for Microspectrophotometry in Forensic Paint
Microscopy/Energy Dispersive X-Ray Spectrometry
Analysis
(SEM/EDS)
E2809 Guide for Using Scanning Electron Microscopy/
E3316 Guide for Forensic Examination of Hair by Micros-
Energy Dispersive X-Ray Spectroscopy (SEM/EDS) in
copy
Forensic Polymer Examinations
E3329 Practice for Establishing an Examination Scheme for
E2882 Guide for Analysis of Clandestine Drug Laboratory
Explosive Residues
Evidence
2.2 ISO Standards:
E2916 Terminology for Digital and Multimedia Evidence
ISO Guide 2 General Terms and Their Definitions Relating
Examination
to Standardizing Activities
E2917 Practice for Forensic Science Practitioner Training,
ISO Guide 30 Terms and Definitions Used in Connection
Continuing Education, and Professional Development
with Reference Materials
Programs
ISO 3534:1993 Statistics—Vocabulary and Symbols
E2927 Test Method for Determination of Trace Elements in
Part 1: Probability and General Statistical Terms
Soda-Lime Glass Samples Using Laser Ablation Induc-
Part 2: Statistical Quality Control
tively Coupled Plasma Mass Spectrometry for Forensic
ISO 3534-1:2006 Statistics—Vocabulary and Symbols—
Comparisons
Part 1: General Statistical Terms and Terms Used in
E2937 Guide for Using Infrared Spectroscopy in Forensic
Probability
Paint Examinations
ISO 3534-2:2006 Statistics—Vocabulary and Symbols—
E2998 Practice for Characterization and Classification of
Part 2: Applied Statistics
Smokeless Powder ISO/IEC 7813:2006 Information Technology—
E2999 Test Method for Analysis of Organic Compounds in
Identification Cards—Financial Transaction Cards
Smokeless Powder by Gas Chromatography-Mass Spec- ISO 9000:2005 (E) Standard Quality Management
trometry and Fourier Transform Infrared Spectroscopy Systems—Fundamentals and Vocabulary
ISO 18158:2016 Workplace Air—Terminology
E3017 Practice for Examining Magnetic Card Readers
ISO 21043-1:2018 Forensic Sciences—Part 1: Terms and
E3085 Guide for Fourier Transform Infrared Spectroscopy
Definitions
in Forensic Tape Examinations
E3115 Guide for Capturing Facial Images for Use with
3. Significance and Use
Facial Recognition Systems
3.1 These terms have application to forensic practice.
E3148 Guide for Postmortem Facial Image Capture
3.1.1 For ASTM International standards, the standard des-
E3149 Guide for Facial Image Comparison Feature List for
ignation is followed by a dash and a two-digit year designation
Morphological Analysis
in bold type, for example, E2161 - 19. The year citation
E3175 Practice for Training in the Forensic Examination of
references the year of publication of the standard from which
Hair by Microscopy
the entry is taken, not necessarily the current year of publica-
E3189 Practice for Separation of Ignitable Liquid Residues
tion of the standard.
from Fire Debris Samples by Static Headspace Concen-
3.1.2 Citations from other than ASTM International stan-
tration onto an Adsorbent Tube
dards may include an abbreviation and the standard number
E3196 Terminology Relating to the Examination of Explo-
followed by a four-digit year designation in bold type, for
sives
example, ISO 9000:2015. The year citation references the year
E3197 Terminology Relating to Examination of Fire Debris
of publication of the standard from which the entry is taken.
E3235 Practice for Latent Print Evidence Imaging Resolu-
Such standards may also be referenced by a name followed by
tion
a year designation, for example, IUPAC Gold Book 2020(1).
E3253 Practice for Establishing an Examination Scheme for
Intact Explosives
Available from International Organization for Standardization (ISO), ISO
E3255 Practice for Quality Assurance of Forensic Science
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
Service Providers Performing Forensic Chemical Analysis
Geneva, Switzerland, http://www.iso.org.
E3260 Guide for Forensic Examination and Comparison of 5
The boldface numbers in parentheses refer to a list of references at the end of
Pressure Sensitive Tapes this standard.
E1732 − 24
Abbreviations are detailed under, “All terms sourced from a convenient adsorption medium for fire debris analysis.
other standards than Committee E30 standards are listed in [E30.01] E3197 - 20
Section 2.”
activation energy, n—amount of energy needed to take the
3.1.3 For entries followed simply by a reference, for
starting materials from their reasonably stable form at 25 °C
example, ISO 9000:2015 or E456 - 17, the reader can assume
and convert them to a reactive, higher-energy excited state.
that the entry is accurately copied from the reference with no
[E30.01] E3196 - 21
modifications except for ASTM International format conven-
tions. For entries that are slightly modified versions of some- ad hoc image, n—see uncontrolled image. [E30.12]
thing from a known source, reference citations read, “Based
E2916 - 19e1
upon definition by…” Following the “by” is the source name
additive (modifier), n—any substance added in a small quan-
and year that the entry was taken or modified. The boldface
tity to improve properties; additives include substances such
numbers in parentheses refer to a list of references at the end
as driers, corrosion inhibitors, catalysts, ultraviolet
of the terminology.
absorbers, and plasticizers. [E30.01] E2937 - 18
3.1.4 For entries from textbooks, a reference following the
entry has the name or title of the text, author(s), edition (if
additive (modifier), n—any substance added in a small quan-
applicable), and the year of publication or copyright.
tity to improve properties. [E30.01] E1610 - 18
3.1.5 An entry could have a definition of a term with one DISCUSSION—Additives can include substances such as driers, corro-
sion inhibitors, catalysts, ultraviolet absorbers, plasticizers, and so
reference, and the discussion following the definition has a
forth.
different reference.
3.1.6 Citations from Merriam-Webster’s Online Diction-
additives, n—materials that are included in adhesive or back-
ary(2) include the date retrieved from the online dictionary and
ing formulations to increase overall volume, impart color, or
the URL of the cited term and definition.
provide other desired properties. [E30.01] E3260 - 21
3.1.7 Each definition is followed by the designation of the
adhesive, n—material that holds two or more objects together
E30 subcommittee responsible shown in square brackets; for
solely by intimate surface contact. [E30.01] E3260 - 21
example, [E30.11].
adsorbent, n—substance that has the ability to condense or
4. Terminology: Terms and Definitions
hold molecules of other substances on its surface.
4.1 Terms and Their Definitions: [E30.01] E3197 - 20
absorbent, n—any substance exhibiting the property of DISCUSSION—Activated carbon, activated alumina, silica gels,
Tenax, and some stationary phase-coated SPME fibers are examples of
absorption. [E30.01] E3197 - 20
adsorbents or adsorbent devices.
absorption, n—penetration of one substance into the inner
adsorption, n—adherence of atoms, ions, or molecules of a gas
structure of another, as distinguished from adsorption, in
or liquid to the surface of another substance. [E30.01]
which one substance is attracted to and held on the surface
E3197 - 20
of another. [E30.01] E3197 - 20
aggregate(s) [clump(s)]—group of soil particles that cohere to
accuracy, n—closeness of agreement between a test result and
each other more strongly than to other surrounding particles.
the accepted reference value. [E30.92] E177 - 19
[E30.11] E3272 - 21
DISCUSSION—In practice, the accepted reference value is substituted
DISCUSSION—Soil aggregates can be natural (a ped) or formed by
for the true value. The term “accuracy,” when applied to a set of test or
human activities (a clod). Often the genesis of evidentiary soil
measurement results, involves a combination of random components
aggregates is unknown, so aggregate is often a preferred term in
and a common systematic error or bias component. Accuracy refers to
descriptions of soil evidence.
a combination of trueness and precision. ISO 3534-2:2006
aggregation, n—collecting of units or parts into a mass or
achievable resolution, resolving power, n—measure of imag-
whole. [E30.01] E1968 - 19, E1969 - 19, E2125 - 19
ing system’s practical limit to distinguish between separate
adjacent elements, typically by imaging a known reference
alibi location(s), n—known location suggested or linked to a
standard. [E30.12] E2916 - 19e1
subject (for example, a subject’s home) that is distinct from
the crime scene. [E30.11] E3272 - 21
acquisition, n—in computer forensics, process of using an
DISCUSSION—The term alibi or alibi location can be perceived
access interface to read digital data from a digital source and
negatively, but comparisons of geological materials from alibi locations
create a destination object. [E30.12] E2916 - 19e1
can be exonerating. Alibi location is used in this standard to be
succinct; however, use of this term in documentation of evidence,
activated carbon, n—form of carbon characterized by high
evidence examination reports, or courtroom testimony is discouraged.
adsorptivity for many gases, vapors, and colloidal solids that
is typically activated by heating to 800 °C to 900 °C with aliphatic, adj—descriptive of one of the major groups of
steam or carbon dioxide, which results in a porous internal organic compounds characterized by normal, branched, or
cyclic chain arrangement of the constituent carbon atoms but
structure; also known as activated charcoal. [E30.01]
E3197 - 20 does not include aromatic compounds. [E30.01] E3197 - 20
activated carbon strip, ACS, n—homogenous mixture of
activated charcoal and an inert polymer formed into a strip; Tenax is a trademark of Buchem B.V. in Apeldoorn, Netherlands.
E1732 − 24
alkadiene, n—class of unsaturated aliphatic hydrocarbons apprenticeship, n—relationship in which an individual works
having two double bonds; also known as diene. [E30.01] for an entity while learning skills. [E30.11] E2917 - 19a
E3197 - 20
archive image, n—in computer forensics, a bit stream dupli-
alkane, n—class of aliphatic hydrocarbons characterized by a cate of data placed on media that is suitable for long-term
straight or branched carbon chain; generic formula C H ;
storage. [E30.12] E2916 - 19e1
n 2n+2
also known as paraffin. [E30.01] E3197 - 20
aromatic, n—major group of unsaturated cyclic hydrocarbons
DISCUSSION—In the plural form, also sometimes used to refer to the
containing one or more rings, typified by benzene, which has
general class of aliphatic compounds that includes branched, normal,
a 6-carbon ring containing nominally three double bonds.
and cycloalkanes.
[E30.01] E3197 - 20
alkene, n—class of unsaturated aliphatic hydrocarbons having
DISCUSSION—In fire debris, this term is typically used to refer to
one or more double bond(s); also known as olefin.
alkylbenzenes, which are benzene rings with aliphatic substitutions.
[E30.01] E3197 - 20
artifact, n—by-product, artificial feature, or change resulting
DISCUSSION—In the plural form, also sometimes used in fire debris
analysis to refer to the general class of aliphatic compounds with one from human activity or a technical process (compare noise).
or more double bonds.
[E30.12] E2916 - 19e1
DISCUSSION—Examples include speckles in a scanned picture,
allocated space, allocated storage, n—in computer forensics,
“blocking” in compressed images, distortion in over-saturated audio,
the portions of storage that are assigned or reserved for
and the automatic creation of temporary files because of normal usage
active instructions or for data. [E30.12] E2916 - 19e1
of a computer.
alloy, n—solid or liquid mixture of two or more metals or one
aspect ratio, n—ratio of the width to the height of a rectangle,
or more metals with certain non-metallic elements as in
such as an image, a pixel, or an active video frame.
carbon steels. [E30.01] E3196 - 21
[E30.12] E2916 - 19e1
anagen, n—active growth phase of a hair follicle in the hair
association, inclusion, n—result of a comparison between two
growth cycle. [E30.01] E3175 - 22, E3316 - 22
hair samples in which the characteristics of the questioned
DISCUSSION—The root from a pulled anagen hair is elongated and is
hair are present in the known sample without any exclusion-
usually fully pigmented.
ary differences and, therefore, the donor of the known hair
ancestral group, n—biogeographic designation of human
sample can be included as a possible source of the ques-
populations (for example, Asian, African, European) whose
tioned hair. [E30.01] E3175 - 22
hair can share similar morphological and microscopic traits. DISCUSSION—A microscopical association of hair cannot identify the
definitive source of a questioned hair to the exclusion of all others and
[E30.01] E3175 - 22, E3316 - 22
the number of individuals who could be included as a possible donor of
DISCUSSION—The racial terms Caucasoid, Mongoloid, and Negroid
a specific hair is unknown and cannot be reliably estimated.
should not be used as these terms are no longer acceptable in the field
of anthropology (the field from which these designations originated).
association, inclusion, n—result of a comparison between two
ANFO, n—mixture that consists of ammonium nitrate and fuel hair samples in which the characteristics of the questioned
oil. [E30.01] E3196 - 21 hair are present in the known sample without any exclusion-
ary differences, and therefore, the donor of the known hair
anion, n—ion having a negative charge. [E30.01] E3196 - 21
sample can be included as a possible source of the ques-
DISCUSSION—Examples of anions are NO3- in KNO3 or ClO4- in
tioned hair. [E30.01] E3316 - 22
NH4ClO4.
DISCUSSION—A microscopical association of hair cannot identify the
anisotropic, adj—characteristic of an object in which the definitive source of a questioned hair to the exclusion of all others, and
the number of individuals who could be included as a possible donor of
refractive index differs depending on the direction of propa-
a specific hair is unknown and cannot be reliably estimated.
gation or vibration of light through the object. [E30.01]
E2228 - 19
associative evidence, n—item(s) that could link a person,
place, or thing with another person, place, or thing.
anthropometric analysis, n—in facial identification, an ex-
[E30.92] E1732 - 22
plicit measurement of landmarks on a face and a comparison
of these measurements between two samples. [E30.12]
attempt, n—in facial identification, a submission of a single
E2916 - 19e1
set of biometric samples to a biometric system for identifi-
cation or verification (compare biometric search).
anti-forensics, n—application of a process to modify, conceal,
[E30.12] E2916 - 19e1
or destroy information to inhibit or prevent the effectiveness
of forensic science examinations. [E30.12] E2916 - 19e1
attenuated total reflection (ATR), n—method of spectropho-
tometric analysis based on the reflection of energy at the
aperture, n—beam-restricting orifice in an electron optical
interface of two media that have different refractive indices
column; the orifice diameter influences the beam current and
and are in intimate contact with each other. [E30.01]
depth of focus. [E30.01] E2809 - 22
E2224 - 19
aperture, n—opening in an optical system that controls the
amount of light passing through a system. [E30.01] audio enhancement, n—processing and filtering of audio
E2224 - 19 recordings to improve the signal quality and intelligibility of
E1732 − 24
the signals of interest, such as speech, by attenuating noise or Becke line, n—bright halo near the boundary of a fiber that
otherwise increasing the signal-to-noise ratio. moves with respect to that boundary as the microscope is
[E30.12] E2916 - 19e1 focused through best focus when the fiber is mounted in a
medium that differs from its refractive index.
background, n—apparent absorption caused by anything other
[E30.01] E2228 - 19
than the substance for which the analysis is being made.
Becke line method, n—method for determining the refractive
[E30.01] E2224 - 19, E131 - 10(2015)
index of a fiber relative to its mountant by noting the
background, n—signal produced by the entire analytical
direction in which the Becke line moves when the focus is
system apart from the material of interest.
changed. [E30.01] E2228 - 19
[E30.01] E2937 - 18, E3085 - 17
DISCUSSION—The Becke line always moves toward the higher refrac-
tive index medium (fiber or mountant) when focus is raised (stage is
background radiation, n—X-rays resulting from scattered
lowered) and towards the lower refractive index medium when focus is
Bremsstrahlung and coherently and incoherently scattered
lowered (stage is raised). At the point where the index of the fiber
tube target peaks. [E30.01] E3295 - 22 matches the index of the mounting medium, the Becke line is no longer
visible. The Becke line is generally viewed at a wavelength of 589 nm
background sample, n—recovered sample from a source
(the D line of Sodium [n ]).
D
believed not to have been exposed to pGSR. [E30.01]
biaxially oriented polypropylene (BOPP), n—oriented poly-
E3309 - 21
propylene film in which the polymer has been stretched in
DISCUSSION—Background samples can be used to establish a thresh-
both the machine direction and cross direction during the
old value.
manufacturing process; tapes with such films cannot be torn
backing, n—thin flexible material to which adhesive is applied.
by hand. [E30.01] E3260 - 21
[E30.01] E3260 - 21
binary explosive, n—high explosive consisting of a separate
backlight, n—in facial identification, a light source placed
oxidizer and fuel that can be acquired, stored, or shipped
behind a subject in a controlled capture that reduces back-
individually but, when combined, form an explosive
ground shadows. [E30.12] E2916 - 19e1
mixture. [E30.01] E3196 - 21
backlit, adj—characteristic of a subject or an object that is binder, n—non-volatile portion of a paint, which serves to bind
illuminated from behind. [E30.12] E2916 - 19e1 or cement the pigment particles together. [E30.01]
E1610 - 18
backscattered electron (BE) imaging, n—technique that uses
binder, n—nonvolatile portion of the liquid vehicle of a
high energy electrons that originate from the primary elec-
coating, which serves to bond or cement the pigment
tron beam of the SEM and are elastically reflected by the
particles together. [E30.01] E2937 - 18
specimen to create an image of the sample; the probability of
backscattering is proportional to atomic number.
binning, n—in facial identification: (1) any technique used by
[E30.01] E2809 - 22
a facial recognition (FR) system to organize or optimize
searching based upon some piece(s) of metadata; (2) the
backsize, n—layer applied to the top side of the backing and its
process of parsing (examining) or classifying data to accel-
purpose is to coat and fill a porous surfaced backing with a
erate or improve biometric matching. [E30.12]
material that is inert to the adhesive formulation to be used.
E2916 - 19e1
[E30.01] E3260 - 21
biometric search, n—submission of a biometric reference as a
ball powders, n—class of smokeless powders produced by a
probe against a biometric system for identification (one-to-
process where the final grain morphologies are spherical,
many) or verification (one-to-one) (compare attempt.)
flattened-ball, or flake. [E30.01] E2998 - 16
[E30.12] E2916 - 19e1
barrier filter, n—filter used in fluorescence microscopy that
birefringence, n—property of some crystals, those having
suppresses unnecessary excitation energy that has not been
more than one refractive index; this property will result in
absorbed by the fiber and selectively transmits only energy
interference colors, which are viewed through a polarized
of greater wavelengths than the cut-off wavelength or within
light microscope. [E30.01] E1968 - 19, E1969 - 19
a specific wavelength range. [E30.01] E2228 - 19
birefringence, n—property of some crystals, those having
base charge, n—main high explosive charge. [E30.01]
more than one refractive index; this will result in interfer-
E3196 - 21
ence colors which are viewed through a polarized light
batch mode search, n—in facial identification, a mode of microscope. [E30.01] E2125 - 19
searching records in an automated system in which a group
birefringence, n—numerical difference in refractive indices
of probes are simultaneously or sequentially launched.
(n) for a fiber, given by the equation:
[E30.12] E2916 - 19e1
ni2n'?
?
batch search mode, n—see batch mode search.
[E30.12] E2916 - 19e1 Birefringence (B) can be calculated by determining the
E1732 − 24
retardation (r) and thickness (T) at a particular point in a booster, n—detonator-sensitive high explosive charge used to
fiber and by using the equation: initiate a main-charge explosive that is usually detonator
insensitive. [E30.01] E3196 - 21
B 5 r nm ⁄1000T µm
~ ! ~ !
[E30.01] E2228 - 19
Bragg equation or Bragg’s law, n—describes the physical
phenomenon of X-ray scattering from a crystallographic
birefringent, adj—material exhibiting birefringence.
three-dimensional lattice plane as nλ = 2dsinθ, in which n is
[E30.01] E1968 - 19, E1969 - 19, E2125 - 19
any integer, λ is the wavelength of the X-ray, d is the crystal
bit depth, n—number of bits (binary digits) used to specify the
plane separation, also known as d-spacing, and θ is the angle
brightness or color range of each pixel in an image sensor.
between the crystal plane and the diffracted beam, also
[E30.12] E3235 - 21
known as the Bragg Angle. [E30.01] E3294 - 22
bit stream, n—continuous stream of bits transmitted over a
braid, n—the intertwining of strands in a braiding process to
channel with no separators between the character groups.
produce a rope structure. [E30.01] E2225 - 23
[E30.12] E2916 - 19e1
branched alkane, n—subclass of aliphatic hydrocarbons with
bit stream duplicate, n—in computer forensics, an exact,
the general formula C H , with subordinate chains
n 2n+2
bit-for-bit reproduction of all data objects independent of
branching off of the main chain; also known as isoparaffin
any physical media upon which that data is stored (compare
and isoalkane. [E30.01] E3197 - 20
copy.) [E30.12] E2916 - 19e1
brisance, n—ability of an explosive to shatter an object when
black powder, n—low explosive composed of potassium
fired in direct contact or in its vicinity. [E30.01] E3196 - 21
nitrate, sulfur, and charcoal; commercial products are gen-
buckling, n—abrupt change in the shape and orientation of a
erally glazed and produced in specific granulation size
hair shaft with or without a slight twist.
ranges. [E30.01] E3196 - 21
[E30.01] E3175 - 22, E3316 - 22
DISCUSSION—Sodium nitrate can be found in place of potassium
nitrate.
cache, n—in computer forensics, a temporary storage area set
black powder substitute, n—commercially produced low aside on a processor, in memory, or in a filesystem to keep
frequently needed data readily available, designed to speed
explosive powder that is designed to replace traditional black
powder in muzzle-loading weapons; formulations can in- up processing and improve performance. [E30.12]
E2916 - 19e1
clude potassium perchlorate in addition to potassium nitrate
or can use other fuels such as ascorbic acid. [E30.01]
calendering, v—method of producing adhesive tape by press-
E3196 - 21
ing an adhesive to a backing material through a series of
DISCUSSION—Many black powder substitutes are sulfur-free.
heated rollers; the surface appearance depends on the type of
blades, n—broad, flat, elongated crystals. [E30.01] E1969 - 19 roller used. [E30.01] E3260 - 21
blank, n—control where a specified component(s) is not
calendering marks, n—characteristic marks left on the back-
present. [E30.11] E3255 - 21 ing material because of the manufacturing process.
DISCUSSION—Blanks with various designations can be specified, such
[E30.01] E3260 - 21
as system blank, process blank, method blank, reagent blank, solvent
calibration, n—set of operations that establishes, under speci-
blank, and so forth. Certain blanks may also serve as a negative control.
fied conditions, the relationship between values indicated by
blasting agent, n—non-detonator sensitive explosive that shall
a measuring instrument or measuring system or values
be initiated by a booster or requires a primer to detonate.
represented by a material, and the corresponding known
[E30.01] E3196 - 21
values of measurement. [E30.92] E1732 - 22
DISCUSSION—Many ammonium-nitrate-based explosives fall into this
DISCUSSION—This definition was originally defined in Terminology
category.
E1187, a standard discontinued by ASTM International.
blasting cap, n—cylindrical shell, usually of metal, containing
calibration standard, n—used to determine the quantitative
both a primary high explosive and a secondary high
analysis for the analyte elements of interest in the glass
explosive, which is used to initiate other explosives; also
matrix. [E30.01] E2927 - 16e1
known as a detonator or cap. [E30.01] E3196 - 21
DISCUSSION—The calibration standard(s) shall have a known elemen-
tal composition including a known uncertainty for the reported ana-
bomb, n—explosive device, usually some kind of container
lytes.
filled with explosive, incendiary material, gas, or other
destructive substance, designed to cause damage by way of candidate list, n—in facial identification, a rank ordered list
thermal, blast, or fragmentation effects on impact or when generated from a facial recognition search. [E30.12]
detonated by a time mechanism, switch, remote control E2916 - 19e1
device, electric match, or lit fuse. [E30.01] E3196 - 21
candidate particles, n—particle(s) classified by the instrument
booby trap, n—device with a hidden or concealed triggering software based on detection of appropriate (as specified in
mechanism designed to be initiated by the victim; also Practice E1588) constituent elements as potential pGSR.
known as a victim-activated device. [E30.01] E3196 - 21 [E30.01] E3309 - 21
E1732 − 24
capacity, n—amount of finished product that could be pro- biometric documents and certifies that the data stored on the
duced either in one batch or over a defined period of time documents are genuine. [E30.12] E2916 - 19e1
and given a set list of variables. [E30.01] E2882 - 19
certified reference material, n—reference material (RM)
cap-sensitive, adj—reliably initiated with a detonator; also characterized by a metrologically valid procedure for one or
known as detonator-sensitive. [E30.01] E3196 - 21 more specified properties and accompanied by an RM
certificate that provides the value of the specified property,
capture, n—(1) the process of recording data such as an image,
its associated uncertainty, and a statement of metrological
video sequence, or audio stream and (2) in facial
traceability. [E30.11] E3255 - 21
identification, the process of collecting a biometric sample
from an individual via a sensor. [E30.12] E2916 - 19e1 chain of custody, n—procedures and documents that account
for the possession of a sample by tracking its handling and
capture, v—to record data, such as an image, video sequence,
storage from its point of collection to its final disposition.
audio stream, or biometric sample to digital storage, often by
[E30.92] E1732 - 22
means of a sensor. [E30.12] E2916 - 19e1
chain reaction, n—self-sustaining chemical or nuclear reac-
capture card, frame grabber, n—piece of computer hardware
tion yielding energy or products that cause further reactions
that accepts an analog or digital signal and outputs the signal
of the same kind. [E30.01] E3196 - 21
as digital data. [E30.12] E2916 - 19e1
characteristic descriptors, n—minutiae of the component
capture device, n—device used in the recording of data.
characteristics. [E30.12] E3149 - 18
[E30.12] E2916 - 19e1
characteristic particles, n—particles that have compositions
carve, v—in computer forensics, to extract a portion of data for
rarely found in particles from any other source.
the purpose of analysis. [E30.12] E2916 - 19e1
[E30.01] E1588 - 20
catagen, n—transitional phase of the hair follicle between the
characteristic X-ray, n—X-ray emission resulting from de-
active growth phase (anagen) and the resting phase (telogen)
excitation of an atom following inner shell ionization.
in the hair growth cycle. [E30.01] E3175 - 22, E3316 - 22
[E30.01] E3295 - 22
catalyst, n—any substance of which a small proportion notably DISCUSSION—The energy of a characteristic X-ray is related to the
atomic number of the atom, providing the basis for energy dispersive
affects the rate of a chemical reaction without itself being
X-ray spectroscopy.
consumed or undergoing a chemical change.
[E30.01] E3196 - 21
charcoal, n—highly porous form of amorphous carbon.
[E30.01] E3196 - 21
catalyst, n—substance whose presence initiates or changes the
rate of a chemical reaction, but does not itself enter into the
charge-coupled device (CCD), n—silicon-based semiconduc-
reaction. [E30.12] E2916 - 19e1
tor chip consisting of a linear or two-dimensional array of
photo sensors or pixels that transfers an electrical charge and
cathodoluminescence, n—emission of photons in the ultravio-
converts it into a digital value. [E30.01] E2808 - 21a
let (UV), visible (Vis), and infrared (IR) regions of the
electromagnetic spectrum as a result of electron beam
charging, n—negative charge accumulation on either a non-
interaction with certain materials. [E30.01] E2809 - 22
conductive sample or a sample that is not properly grounded.
[E30.01] E2809 - 22
cation, n—ion having a positive charge. [E30.01] E3196 - 21
+ + DISCUSSION—This effect may interfere with image formation and
DISCUSSION—Examples of cations are K in KNO or NH in
3 4
X-ray analysis because of beam deflection. It can usually be eliminated
NH ClO .
4 4
by the application of a conductive coating or by the use of a low
vacuum system.
cellophane, n—thin, transparent sheet made of regenerated
cellulose that can be used as a backing material in tape
chemical reaction bomb (CRB), n—device designed to cause
products. [E30.01] E3260 - 21
a mechanical explosion by overpressure of the container
cellulose acetate, n—type of transparent film that is used for because of a chemical reaction, generally produced by the
mixing of commonly available chemicals or products.
tape backings. [E30.01] E3260 - 21
[E30.01] E3196 - 21
DISCUSSION—A matte surface is used for write-on tapes. Cellulose
acetate is more moisture-resistant than cellophane.
DISCUSSION—Examples include the mixing of hydrochloric acid and
aluminum foil and mixing sodium hydroxide, water, and aluminum foil.
cellulosic fiber, n—fiber composed of polymers formed from
clarification, n—see enhancement. [E30.12] E2916 - 19e1
glucose subunits (for example, vegetable, rayon/Lyocell).
[E30.01] E2224 - 19
clarify, n—see enhance. [E30.12] E2916 - 19e1
certification authority, n—(1) in computer forensics, a trusted
class, n—group, set, or kind sharing common attributes (ex-
third party entity that issues digital certificates certifying the
amples provided in Ref (2)). [E30.92] E1732 - 22
ownership of a public key by the subject named in the
certificate, and trusted by both entities engaged in a digital class characteristic(s), n—attribute(s) that establish member-
transaction and (2) in facial identification, a body that issues ship in a class. [E30.92] E1732 - 22
E1732 − 24
classification, n—systematic arrangement of hairs into catego- combustion, n—usually rapid chemical process (such as oxi-
ries (for example, human, animal, somatic origin, ancestry) dation) that produces heat and usually light. [E30.01]
based on shared traits. [E30.01] E3175 - 22, E3316 - 22 E3196 - 21
classification, n—systematic arrangement of persons or objects combustion, n—usually rapid chemical process (as oxidation)
that produces heat and usually light. [E30.01] E3197 - 20
into categories (groups or classes) based on shared traits or
characteristics. (3) [E30.92] E1732 - 22
combustion product, n—heat, gases, volatilized liquids and
clean room, clean chamber, positive air flow cabinet, n—to solids, particulate matter, and ash generated by combustion.
the extent possible, a limited particulate environment. [E30.01] E3197 - 20
[E30.12] E2916 - 19e1
commonly associated particles, n—particles have composi-
DISCUSSION—For example, requirements would follow ISO 5 or
tions that are also commonly found in environmental par-
Class 100 standard for air quality.
ticles from numerous sources. [E30.01] E1588 - 20
clear, v—in computer forensics, to overwrite storage space on
DISCUSSION—However, when present, in addition to particles that are
a medium with non-sensitive data, which may include characteristic of, and/or consistent with GSR, these particles can be of
significance in the interpretation of a population of particles and,
overwriting not only the logical storage location of files, but
consequently, the likelihood that that population is GSR. In isolation,
may include all addressable locations. [E30.12]
however, such particles have little significance in examinations for
E2916 - 19e1
GSR.
cluster, n—in computer forensics, a group of contiguous
comparison microscope, n—system of two microscopes po-
sectors on storage media, typically the smallest unit of
sitioned side-by-side and connected via an optical bridge so
allocation in a filesystem. [E30.12] E2916 - 19e1
that two specimens are examined simultaneously in either
transmitted or reflected light. [E30.01] E2228 - 19
coating, n—generic term for paint, lacquer, enamel, or other
liquid or liquifiable material that is converted to a solid,
comparison sample—fire debris: (1) a sample of material
protective, decorative, or combination thereof film after
collected from a fire scene which is, to the best of the
application. [E30.01] E1610 - 18
collector’s knowledge, similar with respect to relevant char-
acteristics to a sample suspected of containing ignitable
coating, n—generic term for paint, lacquer, enamel, or other
substance, but which is not expected to contain an ignitable
liquid or liquefiable material that is converted to a solid,
substance and (2) a sample of suspected ignitable substance
protective, or decorative film or a combination of these types
submitted for the purpose of comparing with any ignitable
of films after application. [E30.01] E2937 - 18
substance separated from a debris sample. [E30.01]
cocaine, n—either d- or l- cocaine; it should be noted that
E3197 - 20
l-cocaine is the naturally occurring isomer found in the coca
DISCUSSION—A comparison sample should not be confused with a
plant. [E30.01] E1968 - 19
control sample. For example, a comparison sample might include
unburned carpet or flooring that meets the requirements in Ref (2).
codec, n—algorithm to encode and decode digital data, typi-
E1732
cally to reduce the amount of data for transmission or
DISCUSSION—Although, in theory, the use of comparison samples can
storage. [E30.12] E2916 - 19e1
help clarify the presence of a suspected inherent ignitable liquid, the
DISCUSSION—A codec is not a storage format, but may be required to
presence of an ignitable liquid in a comparison sample does not
interpret stored data.
necessarily mean it is inherent to the material.
cognitive image analysis, n—in image and video analysis, a
compensator, n—any variety of optical devices that can be
process used to extract visual information from an image by
placed in the light path of a polarized light microscope to
human evaluation. [E30.12] E2916 - 19e1
introduce known, fixed or variable retardation in a specific
coherent (Rayleigh) scatter peaks—spectral artifacts that
vibration direction; the retardation and sign of elongation of
result from elastic scattering of the tube target characteristic
the fiber can then be determined. [E30.01] E2228 - 19
X-rays by the sample. [E30.01] E3295 - 22
DISCUSSION—Compensators often contain a fixed mineral plate of
DISCUSSION—Because no energy is lost in elastic scattering, coherent
constant or varying thickness or a mineral plate that is rotated, or have
scatter peaks occur at the same energies as the tube target characteristic
its thickness varied by tilting, to alter the thickness presented to the
X-rays.
optical path (and retardation introduced) by a set amount.
color range, n—see gamut. [E30.12] E2916 - 19e1
compensator, full-wave (or red plate), n—compensator (usu-
ally a plate of gypsum, selenite, or quartz) that introduces a
combustible, n—any substance that will burn, regardless of its
fixed retardation between 530 nm to 550 nm (approximately
autoignition temperature, or whether it is a solid, liquid or
the retardation of the first order red color on the Michel-Lévy
gas. [E30.01] E3197 - 20
chart). [E30.01] E2228 - 19
combustible, adj—capable of undergoing combustion.
compensator, quarter-wave, n—a compensator (usually a
[E30.01] E3197 - 20
mica plate) that introduces a fixed retardation between
combustible liquid, n—see ignitable liquid. [E30.01] ~137 nm to 147 nm (approximately the retardation of first-
E3197 - 20 order gray on the Michel-Lévy chart). [E30.01] E2228 - 19
E1732 − 24
compensator, quartz wedge, n—wedge, usually cut from control sample, n—material of established origin that is used
quartz, having continuously variable retardation extending to evaluate the performance of a test or comparison.
over several orders (usually 3 to 7) of interference colors. [E30.92] E1732 - 22
[E30.01] E2228 - 19 DISCUSSION—A control sample should not be confused with a
comparison sample. For example, in fire debris, a control sample might
compensator, Sénarmont, n—quarter-wave plate inserted
include an empty can from the same lot as that used to collect samples.
above the specimen in the parallel “0” position with a
control sample, n—material of established origin that is used
calibrated rotating analyzer; measures low retardation and
to evaluate the performance of a test or comparison.
requires the use of monochromatic light. [E30.01]
[E30.01] E3197 - 20
E2228 - 19
DISCUSSION—A control sample should not be confused with a
comparison sample. For example, in fire debris, a control sample might
compensator, tilting (Berek), n—compensator typically con-
include an empty can from the same lot as that used to collect samples.
taining a plate of calcite or quartz, which can be tilted by
means of a calibrated drum to introduce variable retardation.
controlled image, n—in facial identification, a photographic
[E30.01] E2228 - 19
image captured in accordance with facial i
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1732 − 22 E1732 − 24
Standard Terminology
Relating to Forensic Science
This standard is issued under the fixed designation E1732; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This terminology standard includes definitions of terms used in the forensic sciences.
1.2 Legal and scientific and terms in common use that are generally understood or defined adequately in other readily available
sources may not be included, except when dictionaries show multiple definitions and it seems desirable to indicate the definitions
recommended for forensic science use.
1.3 Section A defines terms that are common to multiple areas of forensic science, whereas, the subsequent sections define terms
pertaining to specific forensic science areas, as follows:
Section A: General (Common) Forensic Science Terms
The terms defined in Section A are the direct responsibility of Subcommittee E30.92, Terminology.
Section B: Criminalistics
The terms defined in Section B are the direct responsibility of Subcommittee E30.01, Criminalistics.
Section B1: Terms for Seized Drug Analysis
Section B2: Terms for Gunshot Residue (GSR) Analysis and Smokeless Powder Analysis
Section B3: Terms for Paint Analysis
Section B4: Terms for Textile, Fiber, Cord, and Tape Examination
Section B5: Terms for Glass Examination
Section B6: Terms for Fire Debris
Section C: Digital and Multimedia Evidence
The terms defined in Section C are the direct responsibility of Subcommittee E30.12, Digital and Multimedia Evidence.
Section C1: Terms for Computer Forensics
Section C2: Terms for Digital Image Processing and Multimedia Evidence Examination
Section C3: Terms for Magnetic Card Reader Examination
Section C4: Terms for Facial Image Examination
Section D: Interdisciplinary
The terms defined in Section D are the direct responsibility of Subcommittee E30.11, Interdisciplinary Forensic Science Standards.
This terminology is under the jurisdiction of ASTM Committee E30 on Forensic Sciences and is the direct responsibility of Subcommittee E30.92 on Terminology.
Current edition approved April 1, 2022Feb. 1, 2024. Published April 2022March 2024. Originally approved in 1995. Last previous edition approved in 20192022 as
ɛ1
E1732 – 19E1732 – 22. . DOI: 10.1520/E1732-22.10.1520/E1732-24.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1732 − 24
Section E: Questioned Documents
The terms defined in Section E were formerly the direct responsibility of Subcommittee E30.02, Questioned Documents, and are currently the direct
responsibility of Subcommittee E30.90, Executive Committee.
1.4 Entries listed in Sections B–E reflect only those existing in Committee E30 standards current with the date of a once yearly
review of Committee E30 standards. Changes to standards or entries following this date will appear in Sections B–E after the
following year’s review date.
1.1 An alphabetical list of the terms defined in this standard is given in This terminology is the compilation of all terms used by
Committee E30 on Forensic Sciences.Appendix X1, which also identifies the section(s) in which each term is defined.
1.1.1 This terminology consists mostly of definitions that are specific to forensic science and forensic practice. Meanings of the
same terms used outside of forensic practice can be found in other compilations or dictionaries of general usage.
1.1.2 The specific E30 subcommittee (SC) that has responsibility for each term is the first attribution noted, in square brackets,
after the definition. The designation of the standard(s) in which the terms appear is given after the subcommittee. The wording of
an entry cannot be changed without approval per the Committee E30 Bylaws. Users of this compilation should also review any
SC terminology standard for more details or interpretations of these terms and their use by the SC.
1.2 Definitions identical to those published by another standards-developing organization or ASTM committee are identified with
the abbreviation of the name of the organization or the identifying document and ASTM committee; for example, ASME is the
American Society of Mechanical Engineers.This terminology is a tool for managing the committee’s terminology. This includes
finding, eliminating, and preventing redundancies in which two or more terms relating the same concept are defined in different
words.
1.7 In some cases different usage of a term in different fields has been noted.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C162 Terminology of Glass and Glass Products
D123 Terminology Relating to Textiles
D6161 Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration, and Reverse Osmosis Membrane Processes
E131 Terminology Relating to Molecular Spectroscopy
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E860 Practice for Examining and Preparing Items That Are or May Become Involved in Criminal or Civil Litigation
E1187 Terminology Relating to Conformity Assessment (Withdrawn 2006)
E1301 Guide for Proficiency Testing by Interlaboratory Comparisons (Withdrawn 2012)
E1402E1388 Guide for Sampling DesignPractice for Static Headspace Sampling of Vapors from Fire Debris Samples
E1412 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Passive Headspace Concentration with
Activated Charcoal
E1413 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Dynamic Headspace Concentration
onto an Adsorbent Tube
E1588 Practice for Gunshot Residue Analysis by Scanning Electron Microscopy/Energy Dispersive X-Ray Spectrometry
E1605 Terminology Relating to Lead in Buildings
E1610 Guide for Forensic Paint Analysis and Comparison
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
E1732 − 24
E1618 Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass
Spectrometry
E1968 Practice for Microcrystal Testing in Forensic Analysis for Cocaine
E1969 Practice for Microcrystal Testing in Forensic Analysis for Methamphetamine and Amphetamine
E2125 Practice for Microcrystal Testing in Forensic Analysis for Phencyclidine and Its Analogues
E2154 Practice for Separation and Concentration of Ignitable Liquid Residues from Fire Debris Samples by Passive Headspace
Concentration with Solid Phase Microextraction (SPME)
E2161 Terminology Relating to Performance Validation in Thermal Analysis and Rheology
E2224 Guide for Forensic Analysis of Fibers by Infrared Spectroscopy
E2225 Guide for Forensic Examination of Fabrics and Cordage
E2227 Guide for Forensic Examination of Dyes in Textile Fibers by Thin-Layer Chromatography
E2228 Guide for Microscopical Examination of Textile Fibers
E2363 Terminology Relating to Manufacturing of Pharmaceutical and Biopharmaceutical Products in the Pharmaceutical and
Biopharmaceutical Industry
E2388 Guide for Minimum Training Requirements for Forensic Document Examiners (Withdrawn 2020)
E2678 Guide for Education and Training in Computer Forensics (Withdrawn 2023)
E2808 Guide for Microspectrophotometry in Forensic Paint Analysis
E2809 Guide for Using Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy (SEM/EDS) in Forensic
Polymer Examinations
E2882 Guide for Analysis of Clandestine Drug Laboratory Evidence
E2916 Terminology for Digital and Multimedia Evidence Examination
E2917 Practice for Forensic Science Practitioner Training, Continuing Education, and Professional Development Programs
E2927 Test Method for Determination of Trace Elements in Soda-Lime Glass Samples Using Laser Ablation Inductively
Coupled Plasma Mass Spectrometry for Forensic Comparisons
E2937 Guide for Using Infrared Spectroscopy in Forensic Paint Examinations
E2998 Practice for Characterization and Classification of Smokeless Powder
E2999 Test Method for Analysis of Organic Compounds in Smokeless Powder by Gas Chromatography-Mass Spectrometry and
Fourier Transform Infrared Spectroscopy
E3017 Practice for Examining Magnetic Card Readers
E3085 Guide for Fourier Transform Infrared Spectroscopy in Forensic Tape Examinations
E3115 Guide for Capturing Facial Images for Use with Facial Recognition Systems
E3148 Guide for Postmortem Facial Image Capture
E3149 Guide for Facial Image Comparison Feature List for Morphological Analysis
E3175 Practice for Training in the Forensic Examination of Hair by Microscopy
E3189 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Static Headspace Concentration onto
an Adsorbent Tube
E3196 Terminology Relating to the Examination of Explosives
E3197 Terminology Relating to Examination of Fire Debris
E3235 Practice for Latent Print Evidence Imaging Resolution
E3253 Practice for Establishing an Examination Scheme for Intact Explosives
E3255 Practice for Quality Assurance of Forensic Science Service Providers Performing Forensic Chemical Analysis
F2725E3260 Guide for European Union’s Registration, Evaluation, and Authorization of Chemicals (REACH) Supply Chain
Information ExchangeForensic Examination and Comparison of Pressure Sensitive Tapes
E3272 Guide for Collection of Soils and Other Geological Evidence for Criminal Forensic Applications
E3294 Guide for Forensic Analysis of Geological Materials by Powder X-Ray Diffraction
E3295 Guide for Using Micro X-Ray Fluorescence (μ-XRF) in Forensic Polymer Examinations
E3296 Guide for Using Pyrolysis Gas Chromatography and Pyrolysis Gas Chromatography-Mass Spectrometry in Forensic
Polymer Examinations
E3309 Guide for Reporting of Forensic Primer Gunshot Residue (pGSR) Analysis by Scanning Electron Microscopy/Energy
Dispersive X-Ray Spectrometry (SEM/EDS)
E3316 Guide for Forensic Examination of Hair by Microscopy
E3329 Practice for Establishing an Examination Scheme for Explosive Residues
2.2 ISO Standards:
ISO 3534:1993 (E/F) Statistics—Vocabulary and Symbols
Part 1: Probability and General Statistical Terms
Part 2: Statistical Quality Control
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
E1732 − 24
ISO 3534–1:2006 Statistics—Vocabulary and Symbols—Part 1: General Statistical Terms and Terms Used in Probability
ISO 3534–2:2006 Statistics—Vocabulary and Symbols—Part 2: Applied Statistics
ISO 9000:2005 (E) Standard Quality Management Systems—Fundamentals and Vocabulary
ISO Guide 2 General Terms and Their Definitions Relating to Standardizing Activities
ISO Guide 30 Terms and Definitions Used in Connection with Reference Materials
ISO Guide 35ISO 3534:1993 Reference Materials—General Statistics—Vocabulary and Symbols
and Statistical PrinciplesPart 1: Probability and General Statistical Terms
for CertificationPart 2: Statistical Quality Control
ISO GUM3534-1:2006 Guide to the Expression of Uncertainty in Measurement (GUM)Statistics—Vocabulary and Symbols—
Part 1: General Statistical Terms and Terms Used in Probability
ISO 3534-2:2006 Statistics—Vocabulary and Symbols— Part 2: Applied Statistics
ISO/IEC 7813:2006ISO/IEC 7813:2006 Information Technology—Identification Cards—Financial Transaction Cards
ISO/IEC 10918-1:1994ISO 9000:2005 Information Technology — Digital Compression and Coding of Continuous-Tone Still
Images: Requirements and Guidelines(E) Standard Quality Management Systems—Fundamentals and Vocabulary
ISO 18158:2016 Workplace air — TerminologyAir—Terminology
ISO 21043-1:2018 Forensic sciences — Part Sciences—Part 1: Terms and definitionsDefinitions
2.3 Other Sources:
ANSI/NIST-ITL 1-2011 Data Format for the Interchange of Fingerprint, Facial, and Other Biometric Information
EURACHEM The Fitness for Purpose of Analytical Methods, EURACHEM Working Group, English Edition
IAAI Glossary Glossary of Terms Related to Chemical and Instrumental Analysis of Fire Debris, IAAI Forensic Science
Committee
IEEE 100-2000 The Authoritative Dictionary of IEEE Standards Terms, 7th Edition
IUPAC Terminology IUPAC Compendium of Chemical Terminology, Second Edition, 1997
JCGM 200:2012 The International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (2.26 [3.9]
VIM)
NIST SP 800-86 Guide to Integrating Forensic Techniques into Incident Response
NIST SP 800-88 Guidelines for Media Sanitization
SWGDRUG
3. Significance and Use
3.1 These terms have particular application to forensic practice. Entries for Section A of E1732 are chosen variously from
Webster’s Online Dictionary, international standards, textbooks, and the Compilation of ASTM Standard Definitions. The
subcommittee develops definitions when conventional sources fail to yield suitable candidates. Reference citations include:
3.1.1 For ASTM International standards, the standard designation is followed by a dash and a two-digit year designation, e.g.,
E2161-19. designation in bold type, for example, E2161 - 19. The year citation references the year of publication of the standard
from which the entry is taken, not necessarily the current year of publication of the standard.
3.1.2 Citations from other than ASTM International standards may include an abbreviation and the standard number followed by
a four-digit year designation, e.g., designation in bold type, for example, ISO 9000:2015. The year citation references the year of
publication of the standard from which the entry is taken. Such standards may also be referenced by a name followed by a year
designation, e.g., for example, IUPAC Gold Book 2020.2020(1). Abbreviations are explicated under “2. Referenced Documents-
.”detailed under, “All terms sourced from other standards than Committee E30 standards are listed in Section 2.”
3.1.3 For entries created by members of E30, a brief statement to that effect and a year designation follows the entry, e.g., Created
by E30 in 2021.
3.1.3 For entries followed simply by a reference, e.g., for example, ISO 9000:2015 or E456E456-17, - 17, the reader can assume
that the entry is accurately copied from the reference with no modifications except for ASTM International format conventions.
For entries that are slightly modified versions of something from a known source, reference citations read, “Based upon definition
by…” Following the “by” is the source name and year that the entry was taken, or modified, for inclusion in Section A. taken or
modified. The boldface numbers in parentheses refer to a list of references at the end of the terminology.
Tenax is a trademark of Buchem B.V. in Apeldoorn, Netherlands.
Available from Institute of Electrical and Electronics Engineers, Inc. (IEEE), 445 Hoes Ln., Piscataway, NJ 08854, http://www.ieee.org.
Available from Joint Committee for Guides in Metrology (JCGM), https://www.bipm.org/en/committees/jc/jcgm.
Available from the Scientific Working Group for the Analysis of Seized Drugs, http://www.swgdrug.org.
The boldface numbers in parentheses refer to a list of references at the end of this standard.
E1732 − 24
3.1.4 For entries from textbooks, a reference following the entry will have has the name or title of the text, author(s), edition (if
applicable)applicable), and the year of publication or copyright.
3.1.6 For entries of unknown origin currently in E1732 Section A, a statement declaring that a review of these entries by E30
occurred in a particular year follows the entry e.g., Reviewed by E30 in 2021.
3.1.5 An entry may be such that the could have a definition of a term has one reference and the DISCUSSION, following the
definition,with one reference, and the discussion following the definition has a different reference.
3.1.6 Citations from Merriam-Webster’s Online Dictionary(2) include the date retrieved from the online dictionary and the URL
of the cited term and definition.
3.1.7 Each definition is followed by the designation of the E30 subcommittee responsible shown in square brackets; for example,
[E30.11].
4. TerminologyTerminology: Terms and Definitions
SECTION A: GENERAL (COMMON) FORENSIC SCIENCE TERMS
The terms defined in Section A are the direct responsibility of Subcommittee E30.92, Terminology.
4.1 Terms and Their Definitions:
absorbent, n—any substance exhibiting the property of absorption. [E30.01] E3197 - 20
absorption, n—penetration of one substance into the inner structure of another, as distinguished from adsorption, in which one
substance is attracted to and held on the surface of another. [E30.01] E3197 - 20
accuracy, n—closeness of agreement between a test result and the accepted reference value. [E30.92] E177 - 19
DISCUSSION—
In practice, the accepted reference value is substituted for the true value. The term “accuracy,” when applied to a set of test or measurement results,
involves a combination of random components and a common systematic error or bias component. Accuracy refers to a combination of trueness and
precision. ISO 3534-2:2006
achievable resolution, resolving power, n—measure of imaging system’s practical limit to distinguish between separate
adjacent elements, typically by imaging a known reference standard. [E30.12] E2916 - 19e1
acquisition, n—in computer forensics, process of using an access interface to read digital data from a digital source and create
a destination object. [E30.12] E2916 - 19e1
activated carbon, n—form of carbon characterized by high adsorptivity for many gases, vapors, and colloidal solids that is
typically activated by heating to 800 °C to 900 °C with steam or carbon dioxide, which results in a porous internal structure;
also known as activated charcoal. [E30.01] E3197 - 20
activated carbon strip, ACS, n—homogenous mixture of activated charcoal and an inert polymer formed into a strip; a
convenient adsorption medium for fire debris analysis. [E30.01] E3197 - 20
activation energy, n—amount of energy needed to take the starting materials from their reasonably stable form at 25 °C and
convert them to a reactive, higher-energy excited state. [E30.01] E3196 - 21
ad hoc image,n—see uncontrolled image. [E30.12] E2916 - 19e1
additive (modifier), n—any substance added in a small quantity to improve properties; additives include substances such as
driers, corrosion inhibitors, catalysts, ultraviolet absorbers, and plasticizers. [E30.01] E2937 - 18
E1732 − 24
additive (modifier), n—any substance added in a small quantity to improve properties. [E30.01] E1610 - 18
DISCUSSION—
Additives can include substances such as driers, corrosion inhibitors, catalysts, ultraviolet absorbers, plasticizers, and so forth.
additives, n—materials that are included in adhesive or backing formulations to increase overall volume, impart color, or
provide other desired properties. [E30.01] E3260 - 21
adhesive, n—material that holds two or more objects together solely by intimate surface contact. [E30.01] E3260 - 21
adsorbent, n—substance that has the ability to condense or hold molecules of other substances on its surface.
[E30.01] E3197 - 20
DISCUSSION—
Activated carbon, activated alumina, silica gels, Tenax, and some stationary phase-coated SPME fibers are examples of adsorbents or adsorbent
devices.
adsorption, n—adherence of atoms, ions, or molecules of a gas or liquid to the surface of another substance. [E30.01]
E3197 - 20
aggregate(s) [clump(s)]—group of soil particles that cohere to each other more strongly than to other surrounding particles.
[E30.11] E3272 - 21
DISCUSSION—
Soil aggregates can be natural (a ped) or formed by human activities (a clod). Often the genesis of evidentiary soil aggregates is unknown, so aggregate
is often a preferred term in descriptions of soil evidence.
aggregation, n—collecting of units or parts into a mass or whole. [E30.01] E1968 - 19, E1969 - 19, E2125 - 19
alibi location(s), n—known location suggested or linked to a subject (for example, a subject’s home) that is distinct from the
crime scene. [E30.11] E3272 - 21
DISCUSSION—
The term alibi or alibi location can be perceived negatively, but comparisons of geological materials from alibi locations can be exonerating. Alibi
location is used in this standard to be succinct; however, use of this term in documentation of evidence, evidence examination reports, or courtroom
testimony is discouraged.
aliphatic, adj—descriptive of one of the major groups of organic compounds characterized by normal, branched, or cyclic chain
arrangement of the constituent carbon atoms but does not include aromatic compounds. [E30.01] E3197 - 20
alkadiene, n—class of unsaturated aliphatic hydrocarbons having two double bonds; also known as diene. [E30.01] E3197 - 20
alkane, n—class of aliphatic hydrocarbons characterized by a straight or branched carbon chain; generic formula C H ; also
n 2n+2
known as paraffin. [E30.01] E3197 - 20
DISCUSSION—
In the plural form, also sometimes used to refer to the general class of aliphatic compounds that includes branched, normal, and cycloalkanes.
alkene, n—class of unsaturated aliphatic hydrocarbons having one or more double bond(s); also known as olefin.
[E30.01] E3197 - 20
DISCUSSION—
In the plural form, also sometimes used in fire debris analysis to refer to the general class of aliphatic compounds with one or more double bonds.
allocated space, allocated storage, n—in computer forensics, the portions of storage that are assigned or reserved for active
instructions or for data. [E30.12] E2916 - 19e1
E1732 − 24
alloy, n—solid or liquid mixture of two or more metals or one or more metals with certain non-metallic elements as in carbon
steels. [E30.01] E3196 - 21
anagen, n—active growth phase of a hair follicle in the hair growth cycle. [E30.01] E3175 - 22, E3316 - 22
DISCUSSION—
The root from a pulled anagen hair is elongated and is usually fully pigmented.
ancestral group, n—biogeographic designation of human populations (for example, Asian, African, European) whose hair can
share similar morphological and microscopic traits. [E30.01] E3175 - 22, E3316 - 22
DISCUSSION—
The racial terms Caucasoid, Mongoloid, and Negroid should not be used as these terms are no longer acceptable in the field of anthropology (the field
from which these designations originated).
ANFO, n—mixture that consists of ammonium nitrate and fuel oil. [E30.01] E3196 - 21
anion, n—ion having a negative charge. [E30.01] E3196 - 21
DISCUSSION—
Examples of anions are NO3- in KNO3 or ClO4- in NH4ClO4.
anisotropic, adj—characteristic of an object in which the refractive index differs depending on the direction of propagation or
vibration of light through the object. [E30.01] E2228 - 19
anthropometric analysis, n—in facial identification, an explicit measurement of landmarks on a face and a comparison of these
measurements between two samples. [E30.12] E2916 - 19e1
anti-forensics, n—application of a process to modify, conceal, or destroy information to inhibit or prevent the effectiveness of
forensic science examinations. [E30.12] E2916 - 19e1
aperture, n—beam-restricting orifice in an electron optical column; the orifice diameter influences the beam current and depth
of focus. [E30.01] E2809 - 22
aperture, n—opening in an optical system that controls the amount of light passing through a system. [E30.01] E2224 - 19
apprenticeship, n—relationship in which an individual works for an entity while learning skills. [E30.11] E2917 - 19a
archive image, n—in computer forensics, a bit stream duplicate of data placed on media that is suitable for long-term storage.
[E30.12] E2916 - 19e1
aromatic, n—major group of unsaturated cyclic hydrocarbons containing one or more rings, typified by benzene, which has a
6-carbon ring containing nominally three double bonds. [E30.01] E3197 - 20
DISCUSSION—
In fire debris, this term is typically used to refer to alkylbenzenes, which are benzene rings with aliphatic substitutions.
artifact, n—by-product, artificial feature, or change resulting from human activity or a technical process (compare noise).
[E30.12] E2916 - 19e1
DISCUSSION—
Examples include speckles in a scanned picture, “blocking” in compressed images, distortion in over-saturated audio, and the automatic creation of
temporary files because of normal usage of a computer.
aspect ratio, n—ratio of the width to the height of a rectangle, such as an image, a pixel, or an active video frame.
[E30.12] E2916 - 19e1
E1732 − 24
association, inclusion, n—result of a comparison between two hair samples in which the characteristics of the questioned hair
are present in the known sample without any exclusionary differences and, therefore, the donor of the known hair sample can
be included as a possible source of the questioned hair. [E30.01] E3175 - 22
DISCUSSION—
A microscopical association of hair cannot identify the definitive source of a questioned hair to the exclusion of all others and the number of individuals
who could be included as a possible donor of a specific hair is unknown and cannot be reliably estimated.
association, inclusion, n—result of a comparison between two hair samples in which the characteristics of the questioned hair
are present in the known sample without any exclusionary differences, and therefore, the donor of the known hair sample can
be included as a possible source of the questioned hair. [E30.01] E3316 - 22
DISCUSSION—
A microscopical association of hair cannot identify the definitive source of a questioned hair to the exclusion of all others, and the number of individuals
who could be included as a possible donor of a specific hair is unknown and cannot be reliably estimated.
associative evidence, n—item(s) that could link a person, place, or thing with another person, place, or thing.
[E30.92] E1732 - 22
attempt, n—in facial identification, a submission of a single set of biometric samples to a biometric system for identification
or verification (compare biometric search).
[E30.12] E2916 - 19e1
attenuated total reflection (ATR), n—method of spectrophotometric analysis based on the reflection of energy at the interface
of two media that have different refractive indices and are in intimate contact with each other. [E30.01] E2224 - 19
audio enhancement, n—processing and filtering of audio recordings to improve the signal quality and intelligibility of the
signals of interest, such as speech, by attenuating noise or otherwise increasing the signal-to-noise ratio.
[E30.12] E2916 - 19e1
background, n—apparent absorption caused by anything other than the substance for which the analysis is being made.
[E30.01] E2224 - 19, E131 - 10(2015)
background, n—signal produced by the entire analytical system apart from the material of interest.
[E30.01] E2937 - 18, E3085 - 17
background radiation, n—X-rays resulting from scattered Bremsstrahlung and coherently and incoherently scattered tube
target peaks. [E30.01] E3295 - 22
background sample, n—recovered sample from a source believed not to have been exposed to pGSR. [E30.01] E3309 - 21
DISCUSSION—
Background samples can be used to establish a threshold value.
backing, n—thin flexible material to which adhesive is applied. [E30.01] E3260 - 21
backlight, n—in facial identification, a light source placed behind a subject in a controlled capture that reduces background
shadows. [E30.12] E2916 - 19e1
backlit, adj—characteristic of a subject or an object that is illuminated from behind. [E30.12] E2916 - 19e1
backscattered electron (BE) imaging, n—technique that uses high energy electrons that originate from the primary electron
E1732 − 24
beam of the SEM and are elastically reflected by the specimen to create an image of the sample; the probability of backscattering
is proportional to atomic number.
[E30.01] E2809 - 22
backsize, n—layer applied to the top side of the backing and its purpose is to coat and fill a porous surfaced backing with a
material that is inert to the adhesive formulation to be used. [E30.01] E3260 - 21
ball powders, n—class of smokeless powders produced by a process where the final grain morphologies are spherical,
flattened-ball, or flake. [E30.01] E2998 - 16
barrier filter, n—filter used in fluorescence microscopy that suppresses unnecessary excitation energy that has not been
absorbed by the fiber and selectively transmits only energy of greater wavelengths than the cut-off wavelength or within a
specific wavelength range. [E30.01] E2228 - 19
base charge, n—main high explosive charge. [E30.01] E3196 - 21
batch mode search, n—in facial identification, a mode of searching records in an automated system in which a group of probes
are simultaneously or sequentially launched.
[E30.12] E2916 - 19e1
batch search mode,n—see batch mode search.
[E30.12] E2916 - 19e1
Becke line, n—bright halo near the boundary of a fiber that moves with respect to that boundary as the microscope is focused
through best focus when the fiber is mounted in a medium that differs from its refractive index.
[E30.01] E2228 - 19
Becke line method, n—method for determining the refractive index of a fiber relative to its mountant by noting the direction
in which the Becke line moves when the focus is changed. [E30.01] E2228 - 19
DISCUSSION—
The Becke line always moves toward the higher refractive index medium (fiber or mountant) when focus is raised (stage is lowered) and towards the
lower refractive index medium when focus is lowered (stage is raised). At the point where the index of the fiber matches the index of the mounting
medium, the Becke line is no longer visible. The Becke line is generally viewed at a wavelength of 589 nm (the D line of Sodium [n ]).
D
biaxially oriented polypropylene (BOPP), n—oriented polypropylene film in which the polymer has been stretched in both the
machine direction and cross direction during the manufacturing process; tapes with such films cannot be torn by hand. [E30.01]
E3260 - 21
binary explosive, n—high explosive consisting of a separate oxidizer and fuel that can be acquired, stored, or shipped
individually but, when combined, form an explosive mixture. [E30.01] E3196 - 21
binder, n—non-volatile portion of a paint, which serves to bind or cement the pigment particles together. [E30.01] E1610 - 18
binder, n—nonvolatile portion of the liquid vehicle of a coating, which serves to bond or cement the pigment particles together.
[E30.01] E2937 - 18
binning, n—in facial identification: (1) any technique used by a facial recognition (FR) system to organize or optimize searching
based upon some piece(s) of metadata; (2) the process of parsing (examining) or classifying data to accelerate or improve
biometric matching. [E30.12] E2916 - 19e1
biometric search, n—submission of a biometric reference as a probe against a biometric system for identification (one-to-many)
or verification (one-to-one) (compare attempt.) [E30.12] E2916 - 19e1
E1732 − 24
birefringence, n—property of some crystals, those having more than one refractive index; this property will result in
interference colors, which are viewed through a polarized light microscope. [E30.01] E1968 - 19, E1969 - 19
birefringence, n—property of some crystals, those having more than one refractive index; this will result in interference colors
which are viewed through a polarized light microscope. [E30.01] E2125 - 19
birefringence, n—numerical difference in refractive indices (n) for a fiber, given by the equation:
n 2n'
i ?
?
Birefringence (B) can be calculated by determining the retardation (r) and thickness (T) at a particular point in a fiber and
by using the equation:
B5 r nm ⁄1000T µm
~ ! ~ !
[E30.01] E2228 - 19
birefringent, adj—material exhibiting birefringence.
[E30.01] E1968 - 19, E1969 - 19, E2125 - 19
bit depth, n—number of bits (binary digits) used to specify the brightness or color range of each pixel in an image sensor.
[E30.12] E3235 - 21
bit stream, n—continuous stream of bits transmitted over a channel with no separators between the character groups. [E30.12]
E2916 - 19e1
bit stream duplicate, n—in computer forensics, an exact, bit-for-bit reproduction of all data objects independent of any physical
media upon which that data is stored (compare copy.) [E30.12] E2916 - 19e1
black powder, n—low explosive composed of potassium nitrate, sulfur, and charcoal; commercial products are generally glazed
and produced in specific granulation size ranges. [E30.01] E3196 - 21
DISCUSSION—
Sodium nitrate can be found in place of potassium nitrate.
black powder substitute, n—commercially produced low explosive powder that is designed to replace traditional black powder
in muzzle-loading weapons; formulations can include potassium perchlorate in addition to potassium nitrate or can use other
fuels such as ascorbic acid. [E30.01] E3196 - 21
DISCUSSION—
Many black powder substitutes are sulfur-free.
blades, n—broad, flat, elongated crystals. [E30.01] E1969 - 19
blank, n—control where a specified component(s) is not present. [E30.11] E3255 - 21
DISCUSSION—
Blanks with various designations can be specified, such as system blank, process blank, method blank, reagent blank, solvent blank, and so forth.
Certain blanks may also serve as a negative control.
blasting agent, n—non-detonator sensitive explosive that shall be initiated by a booster or requires a primer to detonate.
[E30.01] E3196 - 21
DISCUSSION—
Many ammonium-nitrate-based explosives fall into this category.
blasting cap, n—cylindrical shell, usually of metal, containing both a primary high explosive and a secondary high explosive,
which is used to initiate other explosives; also known as a detonator or cap. [E30.01] E3196 - 21
E1732 − 24
bomb, n—explosive device, usually some kind of container filled with explosive, incendiary material, gas, or other destructive
substance, designed to cause damage by way of thermal, blast, or fragmentation effects on impact or when detonated by a time
mechanism, switch, remote control device, electric match, or lit fuse. [E30.01] E3196 - 21
booby trap, n—device with a hidden or concealed triggering mechanism designed to be initiated by the victim; also known as
a victim-activated device. [E30.01] E3196 - 21
booster, n—detonator-sensitive high explosive charge used to initiate a main-charge explosive that is usually detonator
insensitive. [E30.01] E3196 - 21
Bragg equation or Bragg’s law, n—describes the physical phenomenon of X-ray scattering from a crystallographic
three-dimensional lattice plane as nλ = 2dsinθ, in which n is any integer, λ is the wavelength of the X-ray, d is the crystal plane
separation, also known as d-spacing, and θ is the angle between the crystal plane and the diffracted beam, also known as the
Bragg Angle. [E30.01] E3294 - 22
braid, n—the intertwining of strands in a braiding process to produce a rope structure. [E30.01] E2225 - 23
branched alkane, n—subclass of aliphatic hydrocarbons with the general formula C H , with subordinate chains branching
n 2n+2
off of the main chain; also known as isoparaffin and isoalkane. [E30.01] E3197 - 20
brisance, n—ability of an explosive to shatter an object when fired in direct contact or in its vicinity. [E30.01] E3196 - 21
buckling, n—abrupt change in the shape and orientation of a hair shaft with or without a slight twist.
[E30.01] E3175 - 22, E3316 - 22
cache, n—in computer forensics, a temporary storage area set aside on a processor, in memory, or in a filesystem to keep
frequently needed data readily available, designed to speed up processing and improve performance. [E30.12] E2916 - 19e1
calendering, v—method of producing adhesive tape by pressing an adhesive to a backing material through a series of heated
rollers; the surface appearance depends on the type of roller used. [E30.01] E3260 - 21
calendering marks, n—characteristic marks left on the backing material because of the manufacturing process.
[E30.01] E3260 - 21
calibration, n—set of operations that establishes, under specified conditions, the relationship between values indicated by a
measuring instrument or measuring system or values represented by a material, and the corresponding known values of
measurement. [E30.92] E1732 - 22
DISCUSSION—
This definition was originally defined in Terminology E1187, a standard discontinued by ASTM International.
calibration standard, n—used to determine the quantitative analysis for the analyte elements of interest in the glass matrix.
[E30.01] E2927 - 16e1
DISCUSSION—
The calibration standard(s) shall have a known elemental composition including a known uncertainty for the reported analytes.
candidate list, n—in facial identification, a rank ordered list generated from a facial recognition search. [E30.12] E2916 - 19e1
candidate particles, n—particle(s) classified by the instrument software based on detection of appropriate (as specified in
Practice E1588) constituent elements as potential pGSR. [E30.01] E3309 - 21
E1732 − 24
capacity, n—amount of finished product that could be produced either in one batch or over a defined period of time and given
a set list of variables. [E30.01] E2882 - 19
cap-sensitive, adj—reliably initiated with a detonator; also known as detonator-sensitive. [E30.01] E3196 - 21
capture, n—(1) the process of recording data such as an image, video sequence, or audio stream and (2) in facial identification,
the process of collecting a biometric sample from an individual via a sensor. [E30.12] E2916 - 19e1
capture, v—to record data, such as an image, video sequence, audio stream, or biometric sample to digital storage, often by
means of a sensor. [E30.12] E2916 - 19e1
capture card, frame grabber, n—piece of computer hardware that accepts an analog or digital signal and outputs the signal
as digital data. [E30.12] E2916 - 19e1
capture device, n—device used in the recording of data. [E30.12] E2916 - 19e1
carve, v—in computer forensics, to extract a portion of data for the purpose of analysis. [E30.12] E2916 - 19e1
catagen, n—transitional phase of the hair follicle between the active growth phase (anagen) and the resting phase (telogen) in
the hair growth cycle. [E30.01] E3175 - 22, E3316 - 22
catalyst, n—any substance of which a small proportion notably affects the rate of a chemical reaction without itself being
consumed or undergoing a chemical change.
[E30.01] E3196 - 21
catalyst, n—substance whose presence initiates or changes the rate of a chemical reaction, but does not itself enter into the
reaction. [E30.12] E2916 - 19e1
cathodoluminescence, n—emission of photons in the ultraviolet (UV), visible (Vis), and infrared (IR) regions of the
electromagnetic spectrum as a result of electron beam interaction with certain materials. [E30.01] E2809 - 22
cation, n—ion having a positive charge. [E30.01] E3196 - 21
DISCUSSION—
+ +
Examples of cations are K in KNO or NH in NH ClO .
3 4 4 4
cellophane, n—thin, transparent sheet made of regenerated cellulose that can be used as a backing material in tape products.
[E30.01] E3260 - 21
cellulose acetate, n—type of transparent film that is used for tape backings. [E30.01] E3260 - 21
DISCUSSION—
A matte surface is used for write-on tapes. Cellulose acetate is more moisture-resistant than cellophane.
cellulosic fiber, n—fiber composed of polymers formed from glucose subunits (for example, vegetable, rayon/Lyocell).
[E30.01] E2224 - 19
certification authority, n—(1) in computer forensics, a trusted third party entity that issues digital certificates certifying the
ownership of a public key by the subject named in the certificate, and trusted by both entities engaged in a digital transaction
and (2) in facial identification, a body that issues biometric documents and certifies that the data stored on the documents are
genuine. [E30.12] E2916 - 19e1
E1732 − 24
certified reference material, n—reference material (RM) characterized by a metrologically valid procedure for one or more
specified properties and accompanied by an RM certificate that provides the value of the specified property, its associated
uncertainty, and a statement of metrological traceability. [E30.11] E3255 - 21
chain of custody, n—procedures and documents that account for the possession of a sample by tracking its handling and storage
from its point of collection to its final disposition. [E30.92] E1732 - 22
chain reaction, n—self-sustaining chemical or nuclear reaction yielding energy or products that cause further reactions of the
same kind. [E30.01] E3196 - 21
characteristic descriptors, n—minutiae of the component characteristics. [E30.12] E3149 - 18
characteristic particles, n—particles that have compositions rarely found in particles from any other source.
[E30.01] E1588 - 20
characteristic X-ray, n—X-ray emission resulting from de-excitation of an atom following inner shell ionization. [E30.01]
E3295 - 22
DISCUSSION—
The energy of a characteristic X-ray is related to the atomic number of the atom, providing the basis for energy dispersive X-ray spectroscopy.
charcoal, n—highly porous form of amorphous carbon. [E30.01] E3196 - 21
charge-coupled device (CCD), n—silicon-based semiconductor chip consisting of a linear or two-dimensional array of photo
sensors or pixels that transfers an electrical charge and converts it into a digital value. [E30.01] E2808 - 21a
charging, n—negative charge accumulation on either a nonconductive sample or a sample that is not properly grounded.
[E30.01] E2809 - 22
DISCUSSION—
This effect may interfere with image formation and X-ray analysis because of beam deflection. It can usually be eliminated by the application of a
conductive coating or by the use of a low vacuum system.
chemical reaction bomb (CRB), n—device designed to cause a mechanical explosion by overpressure of the container because
of a chemical reaction, generally produced by the mixing of commonly available chemicals or products. [E30.01] E3196 - 21
DISCUSSION—
Examples include the mixing of hydrochloric acid and aluminum foil and mixing sodium hydroxide, water, and aluminum foil.
clarification,n—see enhancement. [E30.12] E2916 - 19e1
clarify,n—see enhance. [E30.12] E2916 - 19e1
class, n—group, set, or kind sharing common attributes (examples provided in Ref (2)). [E30.92] E1732 - 22
class characteristic(s), n—attribute(s) that establish membership in a class. [E30.92] E1732 - 22
classification, n—systematic arrangement of hairs into categories (for example, human, animal, somatic origin, ancestry) based
on shared traits. [E30.01] E3175 - 22, E3316 - 22
classification, n—systematic arrangement of persons or objects into categories (groups or classes) based on shared traits or
characteristics. (3) [E30.92] E1732 - 22
E1732 − 24
clean room, clean chamber, positive air flow cabinet, n—to the extent possible, a limited particulate environment. [E30.12]
E2916 - 19e1
DISCUSSION—
For example, requirements would follow ISO 5 or Class 100 standard for air quality.
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