ch. 4 fingerprinting review
Terms in this set (27)
is the study of fingerprints
what is the scientific name for fingerprints?
who discovered the 9 basic patterns of fingerprints?
Jan Evangelist Ryan
Which scientist determined that fingerprints were never duplicated?
The FBI classifies prints based on a state developed by which scientist?
Henry and Galton
what are fingerprints?
all fingers, toes, feet, and palm are covered in small ridges ???????
where are fingerprints made?
the creation of of fingerprints occurs in a special layer (the basal layer) in the epidermis where new skin cells are produced
Look at diagram
when does a person first grow fingerprints?
fingerprints probably begin forming at the start of the 10th week of pregnancy
how are infants identified?
the 3 principles of fingerprints:
1st: a fingerprint is an individual characteristic; no two fingers have yet to be found to possess
2nd: a fingerprint will remain unchanged during an individuals lifetime
3rd: fingerprints have general ridge patterns that permit them to be systematically classified
fingerprints and classifciations
-arches: ridges enter one side and exit on other
-loops: ridges enter on one side and exit same side
-whorls: consists of circles, more than one loop, or a mixture of pattern types
~double loop whorl
~central pocket whorl
what is a ridge count?
a ridge count is another characteristic that distinguishes one fingerprint from another. the count is made form the center of the core to the edge of the delta
the study of the uniqueness of friction ridge structures and their use for personal identification
on notebook paper
How many points of similarity are required to match/identify a print in the U.S., in the UK?
US: 8 to 12 points
UK: 16 points
-the automated fingerprint identification system-a computer system for storing and retrieving fingerprints
-began in the early 1970s to: ??
-searches large files for a set of prints taken from an individual
-compares a single print, usually a latent print developed from a crime scene
-by the 1990s most large jurisdiction had their own system in place. the problem-a persons fingerprints maybe in one AFIS but not in others
the FBI's integrated automated fingerprint identification system which is a national database of all 10-print cards from all over the country points of similarity
what is the difference between patent, plastic, and latent fingerprints?
-patent: visible prints transferred onto smooth surfaces by blood or other liquids
-plastic: indentations left in soft materials such as clay or wax
-latent: not visible but made so by dusting with powders or the use of chemicals
what is the difference between eccrine, apocrine, and sebaceous secretions?
-eccrine: largely water with most inorganic(amonia, chlorides, metal ions, phosphates) and organic compounds(amino acids, latic acids, urea, sugars) most important for fingerprints
-apocrine: secrete pheromones and other organic materials
-sebaceous: secrete fatty or greasy substances
Describe the processes for each of the following methods of latent print development:
-iodine: in vapor tent, heat solid iodine crystals,use starch solution to fix print
-ninhyrdrin: object dipped in ninhydrin, wait 24 hours
-silver nitrate: dip, spray, or paint surface
-cyanoacrylate: heat sample in vape or tent
-dusting: dusted with powder
Describe the best methods of print development used on:
-glass: cyanoacrylate & dust
-plastic: cyanoacrylate & dust
-wood: silver nitrate
-styrofoam: silver nitrate
What does the print look like when you use each of the following methods of latent print development?
-iodine: brownish print
-silver nitrate: black, or red brown under developed under UV light
-cyanoacrylate: leaves a white, crystalline print
-dust: will be the color of the dust
can fingerprints be erased?
no, if,for example, they are removed w/ chemicals, they will grow back
lip patterns include:
examples of biometrics used to identify suspects:
-retinal or iris patterns
what type of equipment is replacing inked prints?