OSAC Friction Ridge Subcommittee

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction 

Friction Ridge Subcommittee does not support or endorse all the different ways the steps of the ACE‐V process are currently practiced as depict

Friction Ridge Process Map (Current Practice) D

Inquiry Received Case Suitability Case Acceptance Evidence Intake Technical Assessment Feature Assessmen

Select the

individual of

interest to

consider

Suitability

Determination

of Known

Impressions

Feature

comparison

Weighting of

Similarities and

Dissimilarities

Rendering

Conclusion Verific

Introduction to the Friction Ridge Process Map

The friction ridge examination process map offers a visual description of the conventional process used for associating impressions of friction ri

The process is commonly referred to as ACE‐V: Analysis, Comparison, Evaluation, and Verification. In broad strokes, a friction ridge examination 

proceeds as follows: Analysis refers to an initial information‐gathering phase in which the examiner studies the unknown print to assess the qua

detail present. The examiner considers information such as substrate, development method, various levels of ridge detail, and pressure distorti

with the exemplar. Comparison is the side‐by‐side observation of the friction ridge detail in the two impressions to determine the agreement o

Evaluation phase, the examiner assesses the agreement or disagreement of the information observed during Analysis and Comparison and form

agencies is a review of an examiner’s conclusions with knowledge of those conclusions; in other agencies, it is an independent re‐examination b

know the outcome of the first examination. This map does not cover latent processing techniques or how to use AFIS systems including unsolve

This process map was originally created by the NIST/NIJ Expert Working Group on Human Factors in Latent Print Analysis and published in 2012

OSAC Friction Ridge Subcommittee to describe the various steps of the ACE‐V process and the several different ways they are currently practice

community. The OSAC Friction Ridge Subcommittee does not support or endorse all the different ways the steps of the ACE‐V process are curre

process map. As the OSAC Friction Ridge Subcommittee continues to develop standards and best practice recommendations related to the frict

map will be updated to reflect a single standardized process that is recommended for the friction ridge community.

The intended uses of this process map are to facilitate discussions about key decision points in the ACE‐V process, help the research and standa

able to cite the specific latent print activity that their efforts address, and enable laboratory managers to better understand how their protocols 
OSAC Friction Ridge Subcommittee Friction Ridge Process Map (Current Practice) 

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction ridge examination community. The OSAC Frictio

currently practiced as depicted by the process map.

1010 Y

All case acceptance

criteria met?

N

 Approval received? Analysis timeframe appropriate?

 Technically feasible?

 Sufficient quality? Sufficient quantity? Knowns collected properly?

 Analysis requested appropriate? Resources available to address bias?

 FSP agency specific requirements

Inquiry Received

1020

Request

Received?

1030

Assign Case

Priority

1040

Log Chain of

Custody

Y

N

1050

Will case be worked/

assessed by more than

one examiner?

N

Y

Discontinue

assessment and

document per

agency policy

Go to 7000

Discontinue

assessment and

document per

agency policy

Go to 7000

Underlined Word

Word that will be defined

in the glossary

Technology Assist

Describes how technology

aids in the steps on this

page

Documentation

Task or activity of the process

Start/End

Decision

Predefined process (Individual steps not

detailed on map)

Connector

Inputs

Output

Discontinuation of exam

Legend
OSAC Friction Ridge Subcommittee Friction Ridge Process Map (Current Practice) 

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction ridge examination community. The OSAC Frictio

currently practiced as depicted by the process map.

2010

Inventory

(mark and describe

evidence per agency

policy)

Select single Item/l

 Quality/complex Perceived proba

 Administratively  Forensic objectiv Random order Latent to latent

 Case type Priority By item number

 Surface/Substra

2000

Item(s) forwarded to assigned examiner:

 Questioned Exemplars Known Exemplars

 Inked Impressions (exemplars)

 Lift card Digital images of friction ridge detail

 Photo of friction ridge detail

 Physical item Friction fridge skin (hand, foot, finger, etc.)

2030

Is friction ridge

detail present?

2040

Would physical, chemical,

optical, or digital

enhancement processing

be helpful?

N

Y

2060

Is the enhancement

technique available?

(in house or

outsource)

Y

2070

Apply physical,

chemical,

optical, digital

enhancement

(off map

conducted by

examiner or

someone else)

N

Y

2080

Is the Quality and

Quantity sufficient to

proceed to analysis

per agency

policy?

N

Y

2090

Preserve the

friction ridge

detail per

agency policy

N

2050

Have all value

determinations been

made?

2030

Y

2100

Continue without

assessing additional

latents?

2110

If more than one

latent was assessed,

select single latent

for analysis

2020

N

2020

N

2120

Are potential value

determinations

verified prior to

discontinuation of

case?

2130

Impression(s) suitable 

Analysis?

Discontin

examination 

document 

agency po

Go to 700

N

N

Y
OSAC Friction Ridge Subcommittee Friction Ridge Process Map (Current Practice) 

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction ridge examination community. The OSAC Frictio

currently practiced as depicted by the process map.

Latent Analysis ‐ Feature Assessment and Suitability Determination of Latent Impression

Latent(s) of

potential

value

3010

Decide the method(s)

that you will use to do

the visual analysis with

a magnifier, computer

assisted, enlarged

images

3030

Ridge path/Level 2

(described below)

3060

Reliability of

information

(described below)

3040

Level 3 Detail/

Information

(described below)

3050

Contextual

information

(described below)

3020

Ridge Flow/Level 1

(described below)

3070

Document features in

the region of interest,

their reliability (thus

establishing tolerance),

anatomical source and

orientation, and

contextual information

per agency policy

3080

Assign the relative

value and estimated

weight of all available

information (e.g.,

Rarity of group of

features, Complexity,

Confidence, Clarity,

Quantity)

including potential

influential contextual

information

Level 1 detail refers to the overall ridge flow.

 Potential anatomical source and orientation

 Pattern Anchor points/focal points (used to orient and locate you in the print ‐

delta/cores)

 Major Crease (flection) Minor crease/wrinkle Scar Ridge flow

 Impression size and shape

 Ridge count between all of the above

 Distance and angles between all of the above

 Open fields

 Occasional features (warts and healing skin)

level 2 detail refers to individual friction ridge paths, friction ridge events (e.g.,

bifurcations, ending ridges, dots, and continuous ridges), and their relative

arrangements.

Ridge paths – position, length, width, direction, curvature

Minutiae – position and direction

Type of minutiae

Assess individual ridge events

 Detection of ridge events

 Confidence (related to local clarity)

 Noting open fields

Note the spatial relationship of groups of ridge events (assessing rarity)

 Location and orientation of ridge events

 Scars Flexion creases Secondary creases/wrinkles

 Intervening ridge counts and distances/angles

 Combo feature (handshake, snow cone)

 Bifurcation angle

 Incipient ridges (location, direction, width, length)

 Occasional features (warts and healing skin) dysplasia

Determine if the 3rd level detail is reliable, reproducible, clear, and

demonstrable? Consider the following:

 Pores Ridge edges Angles Ridge thickness Ridge gap Ridge cleave? Crease White lines/wrinkles Incipient ridge Accidental features (scars, cuts, warts)

 Morphology of level 2 features

 Reliability refers to the confidence assigned 

ridge features in terms of existence, location

to be reproduced on the corresponding prin

(Incorporate Swgfast 10 definition)

 Anything that affects the appearance of frict

Assess the impact of:

 Substrate Takeaways (negative impressions) Plastic impressions Resolution Wet ridges contaminants etched Development method Deposition pressure Lateral pressure Changes in pressure

 Location on the item

 Information on how evidence was handled

 e.g., CCTV footage that shows how the object was handled

 Crime Scene attendance Crime scene photos

 Police report Simultaneity Prior conclusion (Has a suspect been already identified in a case?)

 Conclusions from other forensic sections

 Case file from original examiner

 Case Context

 Crime type Non case specific examiner background knowledge (e.g. general quality of

known records; Identification rate of similar latent prints)

 Perceived peer ability

 Perceived peer relationships

 Suspect confessions Media coverage Demographic information of subjects involved Priority designations/Time pressure

 Candidate position/spread/score Political pressure Quotas/benchmarks

3110

Are suita

determin

verified p

compari

3090

Document

suitability

determination per

agency policy

To

2020

3120

Impression(s) suitable for

comparison?

Discontinue

examination and

document per

agency policy

Go to 7000

N

N

3100

Have all suitability

determinations

been made

N

Y

 D La T M E S

 P P D Le T D
OSAC Friction Ridge Subcommittee Friction Ridge Process Map (Current Practice) 

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction ridge examination community. The OSAC Frictio

currently practiced as depicted by the process map.

4090

Are there knowns

from multiple

individuals?

N

4110

Are there multiple

known recordings

for that individual?

Y

4120

Retrieve and

document source of

records per agency

policy

4130

Review the desc

and friction ridge 

all known record

ensure that they a

the same source (

inter‐record comp

4100

Select the individual of interest to

consider first/next

Examples of selection criteria:

 Quality/complexity of exemplars

 Administratively chosen Customer driven; investigative

question

 Random order Perceived probative value based

on examiner discretion

Y

4210

Obtained

additional

records?

N

Y

N

4000

Latent(s) deemed

suitable to compare,

Known(s) of

potential value

and available

contextual

information

Technology Assist

 Automated quality mapping tools

 Computer aided or fully automated

feature extraction

 Computer aided documentation

 AFIS searching Candidate list thresholds

 Magnifier
OSAC Friction Ridge Subcommittee Friction Ridge Process Map (Current Practice) 

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction ridge examination community. The OSAC Frictio

currently practiced as depicted by the process map.

5060

Is there sufficient level 1

disagreement to

potentially reach a

conclusion?

5050

Note similarities and

dissimilarities in level 1

detail and document per

agency policy

5030

Select target

group in latent

and attempt to

locate it in the

compared

impression(s)

5040

Was

the target group found in

the compared impression

within your established

tolerance?

5320

Search for additional

similarities as well as

dissimilarities b//n latent and

compared impression within

established tolerance

5070

Would searching a new

target group be beneficial,

necessary, available or

required?

Y

5090

Am I certain of the Q

anatomical source?

Y

5000

Inputs:

Latent(s) and/or

Known impressions

deemed suitable for

comparison and

available contextual

information

5100

Is there additional

information that would

influence my

evaluation?

N

Y N

5130

Document

additional

information used

(e.g. cctv footage

showing how the

weapon was

handled)

5140

Was it helpful?

N

Y

Technology Assist

 Computer aided statistical modeling of weight of evidence

 Computer aided minutiae locating (e.g. ULW ghost cursor)

 Computer aided feature extraction

 Computer aided comparison (360 degree searching)

 Computer aided documentation

 Computer aided selection of the known to compare (AFIS or CAFIS)

 Magnifier

Known Selection Criteria

How do I select which latent/latent or latent/known to

compare first/next? Select the applicable criteria:

 Quality/complexity of impressions

 Administratively chosen Customer driven; investigative question

 Random order Perceived probative value based on examiner

discretion

 Sequential order Process based on grouping latents based on

scene

 Based on scene examination

5010

Select a single latent to compare with

another latent, one known, or a set of

knowns from a single individual

(see known selection criteria box

below)

Inconclusive 2

Individualize

Exclude

Inconclusive 1

Identification

NOT ID’d

Support for exclusion/

different source

Support for identification/

same source

N

Y

N

Y

C

a

5020

Begin side by side

comparison
of 8

e

5230

Note similarities

and

dissimilarities per

agency policy

5350

Will

level 3 detail be

beneficial to your

evaluation?

5410

Is the

reproducibility of

level 3 sufficient to

support

comparison?

5420

Note similarities and

dissimilarities in level 3 detail

and document per agency

policy

5430

Assign the relative value of the

similarities and dissimilarities in friction

ridge level 3 detail given the estimated

weight of all available information

including potential influential contextual

information

N

Y

5360

Does data support

same source more

than different

source?

5200

Was the target group found

in the compared impression

within your established

tolerance?

Y 5320

5270

Would

additional

known records

help?

Y

5390

Are the data

sufficient to the

exclusion of all

others?

N

5400

Is the data in correspondence

sufficient that you would not

expect to see it in a different

source?

Y

N

N

Y

Y

N

Individualize

Identification

5370

Was the

candidate

retrieved from

an AFIS search?

Y

5380

Consider the

possibility of

incidental similarity

N

5280

Obtain additional

knowns from

individual?

Y

N

5080

Will I attempt to

exclude?

NOT ID'd

N

y

5220

Assign the relative value of the

similarities and dissimilarities in

friction ridge detail given the

estimated weight of all available

information including potential

influential contextual information

5250

Does the data

support different

source more than

same source?

5260

Are the data sufficient

to exclude based on

agency policy?

Y Exclude

N

Inconclusive 2

5240

Am I restricted to only

comparing impressions

that are of value for id?

Exclude Inconclusive 1

Y

N N

NN

Y

Support for exclusion/

different source

Support for identification/

same source

6000

6000

6000

5010
OSAC Friction Ridge Subcommittee Friction Ridge Process Map (Current Practice) 

This process map provides a visual description of the various steps of the ACE‐V process and the several different ways they are currently practiced by the friction ridge examination community. The OSAC Frictio

currently practiced as depicted by the process map.

6090

Consensus

decision/

conclusion

reached?

6100

Resolve conflicts

(Follow agency

conflict resolution

policy )

6020

Is verification

required?

(according to

agency policy)

6030

Conduct

blind

verification?

6060

Conduct fully

blinded?

N

6080

Verifier will

conduct an

independent

ACE

examination

(examiner

begins at 2000)

Y

6040

Share case data

(per agency

policy)

6120

Examination

Complete?

Go to

4000

N

6010

Have all comparisons

been completed?

(PAP)

Go to

5000

Y

Y

N

6290

Provide a

verbal?

6270

Consensus

decision/

conclusion

reached?

6280

Resolve conflicts

(Follow agency

conflict resolution

policy )

6200

Verify prelim

result

(according to

agency policy)

6210

Conduct

blind

verification?

6240

Conduct fully

blinded?

N

6260

Verifier will

conduct an

independent

ACE

examination

(examiner

begins at 2000)

Y Y Y

N

N N

Y

6230

Verification

(reapplication of

ACE)/technical

review

N

N

6070

Share limited

case data (per

agency policy)

Y

6110

Update report and

case notes

(PAP)

6250

Share limited

case data (per

agency policy)

6220

Share case data

(per agency

policy)

6050

Verifier will review

initial examiner’s ACE

and confirm that

determinations are well

supported

Y

N

Y

6300

Notify

submitter

and

document

PAP

N

Y

6000

Inputs:

Comparison

conclusions,

suitability

determinations,

and available

contextual

information

Will I issue a

prelim report?

Y

N
Terms and Definitions

b//n - Between

PAP - Per Agency Policy

Administrative Review - An administrative 

review is conducted in order to determine the 

clerical accuracy of reports and case 

documentation and to ensure the examiner has

followed agency policy and procedure. 

Administrative review shall be conducted on all 

cases. Administrative reviewers do not have to 

be trained to competency in friction ridge 

examination (SWGFAST Doc# 16)

Database Search (Closed) – This is sometimes 

used when a database search is conducted with 

an unknown impression against a closed 

database with a limited number of candidates 

e.g. in Case AFIS systems, as opposed to an 

open search where a database search is 

conducted with an unknown impression against 

a global database.

Changes in pressure - Contact pressure is the 

amount of force applied per unit area by the 

finger on the surface. This can affect both the 

extent of the final contact area as well as the 

degree of compression of the ridges and 

possibly of the substrate. The contact pressure 

and any movement encountered when the 

finger makes contact with the substrate can 

also cause the ridges to distort i.e. move closer 

together or further apart. This can then affect 

the distribution of particular features in the 

resultant fingermark and may affect the ability 

to compare the mark to a reference print. 

Complexity - The interplay between quality and 

quantity of minutiae and its relation to the 

decision thresholds. It broadly represents how 

the amount of available information in an

impression directly impacts the decision-making 

process (SWGFAST Doc# 10) Note 1: An 

Impression is considered complex if the 

following modifying factors are present: low 

specificity of features, significant distortion 

(e.g., multiple tap, superimposed impression, 

extreme pressure leading to tonal reversal, and 

slippage), high tolerances, or the original 

conclusion is contested during verification. Note 

2: An Impression is considered as non-complex 

if modifying factors are present such as high 

specificity of features, presence of creases, 

scars, and open fields.

Contaminant - A substance other than a 

naturally occurring constituent of sweat 

secretions from the skin that may be found in 

fingermarks or be the major constituent of 

them (e.g. grease, blood)

Contextual Bias - A cognitive bias caused by 

contextual factors; an unwarranted or 

unintended influence of task-irrelevant 

contextual information on human judgment 

(OSAC Lexicon)

Crease (Major) - Major creases, or permanent 

flexion creases: the named creases that 

separate the joints of the fingers and divide the 

palm (NIST Special Publication 1151)

Crease (Minor) - Cracks, cuts, and thin or 

nonpermanent scars: collectively called linear 

discontinuities (NIST Special Publication 1151)

Database search (open or closed) – The term 

“Closed Search” is sometimes used when a 

database search is conducted with an unknown 

impression against a closed database with a 

limited number of candidates e.g. in Case AFIS 

systems, as opposed to an “Open Search”

where a database search is conducted with an 

unknown impression against a global database

Deposition pressure - Pressure applied during 

the process of contact between the source and 

the substrate 

Development method - A subset of 

visualization where a process applied to the 

fingermark results in it becoming visible in a 
progressive way, producing a gradual change 

from invisible to clearly visible. Most chemical 

and physical processes can be considered to 

‘develop’ impressions.

Direction – This is usually in refence to the 

orientation of the ridge flow (directional 

arrangement of friction ridges), and 

arrangement of friction ridge features as it 

relates to the distal direction, towards the tips 

of the fingers.

Distortion - Variances in the reproduction of 

friction skin caused by factors such as pressure, 

movement, force, and contact.

Double taps/touch – This may be caused by 

movement of the friction ridge skin or surface 

at the time of deposition. Occurs when the 

contact between a source and a substrate is 

partially broken and then the same source 

contacts the same area of substrate again

Environmental Conditions - The nature of the 

environment to which both the mark and 

substrate are exposed is critical in determining 

the changes that may occur over the time of 

exposure, e.g. temperature, humidity, airflow, 

optical radiation and atmospheric pollutants or 

contaminants.

Etched Impression – E.g. impressions on metal 

substrates that become etched into the metal 

through oxidation 

Exclusion - The determination by an examiner 

that there is sufficient quality and quantity of 

detail in disagreement to conclude that two 

areas of friction ridge impressions did not 

originate from the same source (SWGFAST Doc# 

19)

FSP - Forensic science service provider, forensic 

science practitioner

Identification (Also see Individualize) - The 

determination by an examiner that there is 

sufficient quality and quantity of detail in 

agreement to conclude that two friction ridge 

impressions originated from the same source 

(SWGFAST Doc# 19)

Inconclusive - The determination by an 

examiner that there is neither sufficient 

agreement to individualize, nor sufficient 

disagreement to exclude (SWGFAST Doc# 19)

Incipient ridges - A friction ridge not fully 

developed that may appear shorter and thinner 

than fully developed friction ridges (SWGFAST 

Doc# 19)

Inconclusive 1 - This inconclusive conclusion 

results from a lack of complete and legible 

known prints. This means comparisons were 

made to the extent possible, however 

additional clear and completely recorded 

exemplars, to include the required anatomical 

areas, are needed for re-examination (SWGFAST 

Doc# 10 (Draft))

Inconclusive 2 – This inconclusive decision is 

used when on balance, the data supports 

neither same source nor different source (LR1)

Individual - Subject of Interest, Suspect, Subject 

for Elimination

Individualize (Also see “Identification”) - The 

determination by an examiner that there is 

sufficient quality and quantity of detail in 

agreement to conclude that two friction ridge 

impressions originated from the same source

(SWGFAST Doc# 19)

Note: “...It is the position of SWGFAST that 

“individualization” is synonymous with the term 

“identification” as used in friction ridge 

examination. Both are defined as: “the decision 

by an examiner that there are sufficient 

discrimination friction ridge features in 

agreement to conclude that two areas of 

friction ridge impressions originated from the 

same source. The term individualization was 

originally introduced in latent print 
examinations to provide a more specific term 

than identification. In the friction ridge 

community, identification has historically meant 

association with a specific individual, while in 

some forensic disciplines it is used to denote 

the correspondence of class characteristics. 

SWGFAST recognizes that individualization has 

been used within the latent print community to 

mean “to the exclusion of all others.” The ability 

of a latent print examiner to individualize a 

single latent impression, with the implication 

that they have definitely excluded all other 

humans in the world, is not supported by 

research and was removed from SWGFAST’s 

definition of individualization (SWGFAST Doc# 

103

Knowns (Known Exemplars) - The prints of an 

individual, associated with a known or claimed 

identity, and deliberately recorded 

electronically, by ink, or by another medium 

(also known as known prints) (SWGFAST Doc# 

19)

Lateral pressure – Pressure applied in a 

sideways manner as opposed to directly 

downward, during transfer of the impression 

onto the substrate. This can result in slippage or 

twisting and distortion of the impression

Lateral reversal - Impression may be flipped 

left-for-right, e.g. such as in some impressions

on transparent tape (NIST Special Publication 

1151)

Matrix - The substance that is deposited or 

removed by the friction ridge skin when making 

an impression (SWGFAST Doc# 19)

Open fields - Areas of continuous ridge flow 

where no individual ridge events are occurring

Plastic impressions - Created when the 

substrate is pliable enough at the time of 

contact to record the three-dimensional aspects 

of the friction skin. These impressions are 

formed when the raised friction ridges are 

physically pushed into the substrate, creating a 

mold of the friction skin ridge structure (The 

Fingerprint Sourcebook. Chapter 7.1.1)

Post deposition damage – Refers to damage 

occurring to the impression after deposition e.g. 

overlaying additional impressions onto the 

original impression, areas of the impression 

being removed through friction with other 

objects or environmental conditions having 

deleterious effects on the impression

Potential Value - A technical assessment that 

an impression has sufficient quantity and 

quality of friction ridge detail to proceed on to 

the ACE-V methodology. This decision is a utility 

decision and will be impacted PAP (Task Group 

Discussion)

Preservation method - Recording techniques, 

such as photography, lifting, live-scan, and ink.

Reliability (Reproducibility) - Refers to the 

confidence assigned by the examiner to the 

observed ridge features in terms of existence, 

location, and shape he or she would expect to 

be reproduced on the corresponding print, 

should it be made available. (SWGFAST Doc# 

10)

Region of interest (ROI) - A single continuous 

friction ridge impression (NIST Special 

Publication 1151)

Resolution - Is measured 

in pixels and megapixels. The number of pixels 

that a camera catches in a single photograph is 

known and quantified as the resolution

Simultaneous impression - Two or more friction 

ridge impressions from the same hand or foot 

deposited concurrently (SWGFAST Doc# 19)

Skin condition of the donor - E.g., damage due 

to scars, warts, dryness, certain occupations 

involving physical labor, or illness.
Substrate - The surface upon which a friction 

ridge impression is deposited (SWGFAST Doc# 

19)

Surface – See Substrate.

Specificity – As opposed to sensitivity, assessing 

the impressions intrinsic value, i.e. its capacity 

to discriminate against impressions from 

different individuals. Specificity is related to the 

between source variability, how features in 

impressions will vary when they are left by 

different sources (adapted from Champod).

Also - Weighted Values and rarity (SWGFAST 

Doc# 10).

Sufficiency - The product of the quality and 

quantity of the objective data under 

observation (e.g., friction ridge, crease, and scar 

features) (SWGFAST Doc# 19)

Sufficient - The determination that there is 

sufficiency in a comparison to reach a 

conclusion at the evaluation stage (SWGFAST 

Doc# 19)

Suitable - The determination that there is 

sufficiency in an impression to be of value for 

further analysis or comparison (SWGFAST Doc# 

19)

Support for exclusion/different source - The 

conclusion that the observations provide more 

support for the proposition that the 

impressions originated from different sources 

rather than the same source; however, there is 

insufficient support for a Source Exclusion. The 

degree of support may range from limited to 

strong or similar descriptors of the degree of 

support. Any use of this conclusion shall include 

a statement of the degree of support and the 

factor(s) limiting a stronger conclusion (OSAC 

Standard for Friction Ridge Examination 

Conclusions, Draft)

Support for identification/same source - The 

conclusion that the observations provide more 

support for the proposition that the 

impressions originated from the same source 

rather than different sources; however, there is 

insufficient support for a Source Identification. 

The degree of support may range from limited 

to strong or similar descriptors of the degree of 

support. Any use of this conclusion shall include 

a statement of the degree of support and the 

factor(s) limiting a stronger conclusion (OSAC 

Standard for Friction Ridge Examination 

Conclusions, Draft)

Takeaways (negative impressions) - The 

outcome of a contact between a finger and a 

substrate where material has been transferred 

from the surface to the finger, i.e. material has 

been selectively removed from the surface at 

the points of contact.

Target Group - A distinctive group of ridge 

features (and their relationships) that can be 

recognized (SWGFAST Doc# 19)

Technical Review - Review of notes, documents, 

and other data that forms the basis for a 

scientific conclusion (SWGFAST Doc# 19)

Type of features - Level 1 detail refers to the

overall ridge flow. Level 2 detail refers to 

individual friction ridge paths, friction ridge 

events (e.g., bifurcations, ending ridges, dots, 

and continuous ridges), and their relative 

arrangements. Level 3 detail refers to ridge 

structures (edge shapes and pores), and their 

relative arrangements. Creases, scars, warts, 

incipient ridges, and other features may be 

reflected in all three levels of details.

Tolerance - The allowance of variation in 

appearance of friction ridge features (due to the 

factors listed in reliability of Information), that

will be accepted during comparison, should the 

corresponding print be available (for example, 

High tolerances: generous allowances for 

variations) (SWGFAST Doc #10)
Tonal reversal - Indicates if all or part of the 

image is reversed tonally (black for white), (NIST 

Special Publication 1151)

Verification - Confirmation, through the 

provision of objective evidence, that specified 

requirements have been fulfilled (ISO 9000: 

2015)

Verification (Blind) - The independent 

examination of one or more friction ridge 

impressions at any stage of the ACE process by

another competent examiner who is provided 

with no, or limited, contextual information, and 

has no expectation or knowledge of the 

determinations or conclusions of the original 

examiner. (SWGFAST Doc# 19)

Wet ridges – When friction ridge skin is wet 

with perspiration or contaminants like blood, it 

is possible during the deposition onto the 

substrate, that the moisture is forced into the 

furrows, leaving the areas where the ridges 

make contact, with less matrix. This may result 

in a negative (Take away) impression.

Resources

Champod, C. Lennard, C., Margot, P., Stoilovic, 

M (2016). Fingerprints and Other Ridge Skin 

Impressions, Second Edition. Boca Raton, FL: 

CRC Press, Taylor & Francis Group 

ISO 9000: 2015, Quality management systems 

— Fundamentals and vocabulary

NIST Special Publication 1151, Markup 

Instructions for Extended Friction Ridge 

Features, 2013: 

http://dx.doi.org/10.6028/NIST.SP.1151

SWGFAST Doc# 10, Scientific Working Group for 

Friction Ridge Analysis, Study, and Technology 

(SWGFAST). (03/13/2013). Document #10 

Standards for Examining Friction Ridge 

Impressions and Resulting Conclusions

SWGFAST Doc# 10 (Draft), Standards for 

Examining Friction Ridge Impressions and 

Resulting Conclusions (Draft for Comment Only 

Section 5.3.2.3 (PAGE 4))

SWGFAST Document 19 (2012), Standard 

Terminology of Friction Ridge Examination 

(Latent/Tenprint), Ver. 4.0

SWGFAST Document #103,

Individualization/Identification Position 

Statement 

The Fingerprint Sourcebook. Chapter 7.1.1