Michele Triplett's Fingerprint Terms ©
A collection of over 1000 terms used in the Science of Fingerprint Identification.

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LCV
Leucocrystal Violet.  Reagent used to detect / enhance bloody friction 
ridge detail by either fluorescent or nonfluorescent staining.
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

Langenburg, Glenn
Glenn Langenburg earned a BS in Forensic Science from Michigan State University in 1993 
and a MS in Analytical Chemistry in 1999 from the University of Minnesota. He earned 
his PhD in 2012 from the University of Lausanne, Switzerland, researching the statistical 
analysis of fingerprint comparison methodology.  In addition to his duties as a forensic 
scientist, Glenn is an adjunct professor at two universities in Minnesota: Hamline 
University and Metropolitan State University and served as a member of SWGFAST.

Langerhans Cells
Cells in the stratum spinosum layer of the epidermis designed to process 
foreign antibodies to the immune system.

Langill Decision (2007)
See State of New Hampshire v. Richard Langill.

Laser
Light Amplification by Stimulated Emission of Radiation.  A device that 
produces a coherent wavelength(s) of light. See FLS
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

First used for viewing latent prints by a team of Canadian researchers in 1976.  
These researchers were E. Roland Menzel of Texas Tech University, Brian E. 
Dalrymple of the Ontario Provincial Police, and J.M. Duff of the Xerox Research 
Centre of Canada.
J. Forensic Sci. 22, (1), 106 (1977).
A special lens is used to expand the laser beam to the entire viewing area.  
The first testimony in the United States regarding this method of visualization 
was in 1981 in Sierra Vista, Arizona by Ed German.

Latent Print 
A transferred impression of friction ridge detail that is not readily visible to the 
naked eye; A generic term used for a friction ridge impression that was not intentionally 
recorded.

A fingerprint that is not apparent to the eye but can be made sufficiently visible, as 
by dusting or fuming, for use in identification.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved
http://dictionary.reference.com/search?q=latent&r=3 02-27-03

1. Transferred impression of friction ridge detail not readily visible.
2. Generic term used for unintentionally deposited friction ridge detail.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0

Latent Print Age Determination
The length of time a latent print can remain on an item is dependent on the latent print 
composition, the environment factors, and the substrate. A latent print made up of perspiration 
may evaporate quickly while a latent print composed of fatty material may remain on an item for 
years. The age of a latent print cannot be determined by visualizing the latent print.

Latent Print Composition
A latent print is composed of the material transferred from the friction skin onto an item. 
The composition can be eccrine sweat, sebaceous sweat, blood, oil, paint, lotion, etc. The 
composition of a latent print can only be determined by chemical analysis and should not be 
presumed to be perspiration.

Latent Print Examiner
See Friction Ridge Examiner.

Latent Print Recovery Conditions
Whether or not a latent is recovered is dependant on:
1. The surface (substrate): 
	a) Its physical composition,
	b) Its texture, 
  	c) Condition, 
 	d) and cleanliness.
2. The person touching the item:
 	 a) The condition of their ridges (which could be affected by medical 
	condition or occupation), 
 	 b) how much they sweat (which is dependant on age, diet, temperature, 
	emotional state, medical condition and the recent amount of physical exertion),
 	 c) And the pressure they apply.
3. Whether or not there is a transferable substance on the friction skin other than sweat.
4. Post transfer conditions:
  	a) The environment (heat or rain will deteriorate a latent), 
  	b) How it's handled (handling and packaging may destroy a latent) 
 	c) and the developing medium.

Latzina, Dr. Francisco
A fingerprint pioneer that is credited with influencing Vucetich to change 
the name of his classification system from Icnofalangometria to Dactiloscopy.

Law of ACE’s
“… a process of Analysis, Comparison, and Evaluation (Huber's law of ACE's)." 
Chapter 5, Handwriting Identification: Facts and Fundamentals, Roy A. Huber 
and A.M. Headrick 1999 CRC Press

Law of Biological Uniqueness
The Scientific Law that states that all items in nature are unique.

Laws 
Generalizations about what has happened, from which we can 
generalize about what we expect to happen. They pertain to 
observational data. The ability of the ancients to predict 
eclipses had nothing to do with whether they knew just how 
they happened; they had a law but not a theory. 
http://www.madsci.org/posts/archives/oct99/940942724.Sh.r.html 02-27-03

States an observation without any attempt to explain it (law of gravity).

Leadbetter, Martin FFS, RFP, Bachelor of Arts + Honours
Martin Leadbetter was employed within the Fingerprint Branch at New Scotland 
Yard from 1966/72.  During this period he was also responsible for attending 
crime scenes in Central London as a Divisional Fingerprint Officer.  Having 
qualified as a Fingerprint Expert in 1972, he transferred to the Gloucestershire 
Constabulary where he remained employed for just over two years, after which he 
took up the post of Deputy Head of the Fingerprint Bureau for Hertfordshire 
Constabulary, just north of London.   

In 1988 he was seconded to the Home Office as part of the team investigating 
implementation of a national AFIS for England and Wales.  This secondment lasted 
until 1991 and during this time he assisted in the writing of the Detailed 
Operation Requirement for a national AFIS and made several visits with the bench-
marking team to the USA and France where systems produced by Printrak, NEC, Morpho 
Systèmes (now Sagem) and ISS were all tested.  

From January 1991/August 1995 he was employed by Sagem SA as Fingerprint Expert 
and Consultant.  During this period he visited the police departments of more than 
thirty countries worldwide, including two visits to Siberia, South American countries, 
South Africa, numerous visits to the USA, Russia and most European countries. 
 
In September 1995 he took up his present post as Head of the Fingerprint Bureau for 
Cambridgeshire Constabulary, based in the East Anglian region of the UK.

He has been a member of IAI since 1978, a Distinguished Member since 1988 and achieved 
Life Membership in 2003.  He is a Founder, Fellow and Life Member of The Fingerprint 
Society and was its first Secretary and Assistant Editor of the Society's journal, 
Fingerprint Whorld for just on fifteen years.  Today, Mr. Leadbetter is a serving 
member of The Fingerprint Society Committee.  Recently, he has acted in a consultative 
position in Bosnia, assisting the European Union Police to implement a national AFIS 
for that country.  He has addressed several conferences, both at home and abroad, in 
particular at the Humboldt University, East Berlin, Surgut, Siberia and most recently, 
in October 2004 at the Centenary Conference in Budapest, which celebrated the first 
hundred years of the fingerprint system in Hungary.

At home he is now very active holding several important national posts.  He is a member 
of the National Fingerprint Board of England and Wales, Chairman of the Bureau 
Practitioners' Sub-Group and a member of the Standards Working Group.  Until recently 
he chaired the Third Level Detail Sub-Group, which had been instigated by the 
Association of Chief Police Officers to investigate the potential use of so-called 
'third level detail' within the identification process. He also sits on the IAI's 
International Committee and is a member of the Journal of Forensic Identification's 
Editorial Board.

He is a Registered Forensic Practitioner with the Council for the registration of Forensic 
Practitioners and Member of the British Academy of Forensic Sciences and holds the degree 
of Bachelor of Arts with Honours.

Throughout his long career within the fingerprint discipline he has been a constant 
contributor to forensic and scientific journals.  He strongly holds the view that 
fingerprint identification is not a science, but a technique that requires 
considerable skill, but is prepared to compromise and accept that it has a scientific, 
albeit a rather nebulous 'scientific' basis.

In his spare time Martin Leadbetter enjoys gourmet cooking, wine and is a composer having 
written three symphonies, numerous works for chamber and instrumental ensembles, more than 
fifty songs, and works for choir, band and orchestra.  He is also a Member of the 
Corporation of the Royal Albert Hall, London. As an author he has just completed his first 
full-length novel, Deep and Crisp and Evil, which gives an uncompromising insight into the 
working of the modern police service and forensic discipline.  
11-24-2004

Martin Leadbetter retired from the Cambridgeshire Constabulary on Aug. 12, 2005.

Leuco Rhodamine 6G
A reagent that reacts with the heme moiety of the hemoglobin of red cells in 
blood to visualize friction ridge detail left in blood.  The sulfosalicylic 
acid in this solution fixes the blood so no pretreatment is necessary.
Luo Yapping and Wang Yue.  Journal of Forensic Identification Vol. 54, No. 5, 2004

Leucocrystal Violet
A colorless or reduced form of gentian violet (per the FBI) used 
to stain blood residue (through oxidation) on both porous and 
nonporous items.  Aka LCV.

Leucomalachite Green
Reagent used to detect / enhance bloody friction ridge detail.
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

LeuR6G
See Leuco rhodamine 6G.

Level 1 detail
General overall pattern shape, i.e., circular, looping, arching, or straight.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press

In Nov. 2004, the Third Level Detail working group (from the Standards Sub-Group of the 
National Fingerprint Board of England and Wales) determined that it was not necessary to 
subdivide the features used in friction ridge identifications.  In England and Wales these 
terms are no longer recognized and it has been established that they should not be used. 
See Features.

Friction ridge flow, pattern type, and general morphological information.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0

Level 2 detail
Ridge path, major ridge path deviations, and paths caused by damage such as scars.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press

In Nov. 2004, the Third Level Detail working group (from the Standards Sub-Group of the 
National Fingerprint Board of England and Wales) determined that it was not necessary to 
subdivide the features used in friction ridge identifications.  In England and Wales these 
terms are no longer recognized and it has been established that they should not be used. 
See Features.

Individual friction ridge paths and associated events, including minutiae.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0

Level 3 detail
Ridge shape, relative pore location, and some accidental details.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press

In Nov. 2004, the Third Level Detail working group (from the Standards Sub-Group of the 
National Fingerprint Board of England and Wales) determined that it was not necessary to 
subdivide the features used in friction ridge identifications.  In England and Wales these 
terms are no longer recognized and it has been established that they should not be used. 
See Features.

Friction ridge dimensional attributes, such as width, edge shapes, and pores.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0

Lift
An adhesive or other medium used to transfer a friction ridge impression from a 
substrate.
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0

Light Wavelengths
Ultraviolet light	wavelengths approx. 10nm-400nm
	UV-C		wavelengths approx. 200nm-280nm (dangerous)
	UV-B		wavelengths approx. 280nm-315nm (hazardous)
	UV-A		wavelengths approx. 315nm-400nm
	Black light	wavelengths approx. 345nm-400nm

Visible light	wavelengths approx. 400nm-700nm
	Purple		wavelengths approx. 410nm
	Blue		wavelengths approx. 475nm
	Green		wavelengths approx. 510nm
	Yellow		wavelengths approx. 570nm
	Orange		wavelengths approx. 590nm
	Red		wavelengths approx. 650-700nm

Infrared light	wavelengths approx. 700nm-1,000,000 nm

Visible light is sometimes referred to as white light.  Technically speaking, 
white light is a combination of all the colors in the visible light spectrum.

Lighting Techniques
Ambient, oblique or direct lighting are the most common types used 
in this field.

Lights Out
A computer process where the AFIS computer automatically extracts friction skin features, 
searches the AFIS database, and effects an identification or exclusion based on a 
predefined threshold score. No human is involved in the decision making process. This 
technology became available around 2007 for tenprint operations.

Ligroine
See Petroleum ether.
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

Likelihood Ratios
The ratio comparing two different likelihood functions.

Lipids
Fats or fat-like substances that are insoluble in water.
Quantitative-Qualitative Friction Ridge Analysis, David R. Ashbaugh 1999 CRC Press

The major component of sebaceous sweat, which includes fats, oils and waxes.

Liquid Nitrogen
An element used in its liquid state (-195 degree C)for the separation of 
adhesive surfaces, as well as to enhance the fluorescence of Zinc Chloride 
and Zinc Nitrate treated prints for visualization and photography.
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

Liqui-drox
Fluorescent yellow solution used to develop friction ridge detail on the 
adhesive and non-adhesive sides of dark colored tape.
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

Liqui-nox ®
Detergent used in a solution to develop friction ridge detail on adhesive 
and non-adhesive sides of tape; cleaning agent.
SWGFAST, Glossary - Consolidated 09-09-03 ver. 1.0
http://www.swgfast.org/Glossary_Consolidated_ver_1.pdf

Locard, Edmond (1877-1966)
A major contributor in criminalistics in the early 1900’s.  Locard trained 
as a medical doctor in Lyon and did a thesis with Lacassagne. Lyon was at 
that time one of the best places for forensic medicine in Europe (under the 
guidance of Lacassagne).

In 1910, while successor to Lacassagne as Professor of Forensic Medicine at 
the University of Lyon, France, Locard established the first police crime 
laboratory.
In 1912, Locard established Poroscopy.
In the early 1910’s, Edmond Locard published his Tripartite Rule stating how 
many Galton points were needed to make a positive fingerprint identification.  
Locard's rule appears to have been based on his own work as well as the work 
of others (Galton, Balthazard, etc.) 
Due to some of Locard’s writings from the 1920’s and 30’s, the concept of the 
unintentional transfer of different minute materials between objects became 
known as Locard’s Exchange Principle (aka Locard’s Principle of Exchange).  
Locard was not the only person to recognize and publish this information but 
he did articulate in better than others.

Locard's Principle of Exchange (aka Locards Exchange Principle)
Edmond Locard's Principle of Exchange states that when any two objects come 
into contact, there is always transference of material from each object 
onto the other.
http://www.computing.surrey.ac.uk/ai/impress/ 06-19-2003

Lockheed-Martin 50k x 50k Study (1999)
See FBI / Lockheed-Martin 50k x 50k Study (1999).

Loop
A type of pattern in which one or more friction ridges enters an area, recurves, 
and flows out the same side the friction ridges entered.  Loops can be slanted 
to the right or left and be designated as either radial or ulnar loops.

A pattern type in which one or more friction ridges enter upon one side, recurve, 
touch or pass an imaginary line between delta and core and flow out, or tend to 
flow out, on the same side the friction ridges entered. Types include left slant 
loops, in which the pattern flows to the left in the impression; right slant loops, 
in which the pattern flows to the right in the impression; radial loops, in which 
the pattern flows in the direction of the radius bone of the forearm (toward the 
thumb); and ulnar loops, in which the pattern flows in the direction of the ulna 
bone of the forearm (toward the little finger).
SWGFAST, Standard Terminology of Friction Ridge Examination 3-23-11 ver. 3.0

Loop - Radial
A type of pattern in which one or more friction ridges enter upon either side, 
recurve, touch or pass an imaginary line between delta and core and flow out, 
or tend to flow out, on the same side the friction ridges entered. The flow of 
the pattern runs in the direction of the radius bone of the forearm (toward 
the thumb).
SWGFAST, Glossary 07-28-2009 ver. 2.0

Loop - Ulnar
A type of pattern in which one or more friction ridges enter upon either side, 
recurve, touch or pass an imaginary line between delta and core and flow out, 
or tend to flow out, on the same side the friction ridges entered. The flow of 
the pattern runs in the direction of the ulna bone of the forearm (toward the 
little finger).
SWGFAST, Glossary 07-28-2009 ver. 2.0

Lophoscopy
The study of the development, the classification, and the identification 
of the prints left by the papillary ridges of the skin.
http://users.tpg.com.au/kjw18/fingerprints/Referen/Fpterm/LTERM.HTM 11-12-2005

Loupe
A small magnifying glass.

Luminescence
Any form of light produced by a source other than heat, cool light (chemical, 
electrical).

Luminol
Luminol is a chemical that glows greenish-blue when it comes into contact 
with blood (and some other items)- even traces that are years old. To be 
exact, it reacts to hemoglobin, an oxygen-carrying protein in red-blood 
cells. Luminol is so sensitive, it can detect blood at 1 part per million. 
In other words, if there is one drop of blood within a container of 999,999 
drops of water, luminol will glow.
http://dsc.discovery.com/fansites/onthecase/toolbox/tool_01.html



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Copyright © 2002-2017, Michele Triplett. All rights reserved.