FIS 201 – Mechanics of Materials Mohr’s Circle Analysis
Exam 3 Comprehensive Study Notes
When is trace evidence formed? - correct answer ✔✔ generated when objects touch each other
and remains of material are left behind
What is a latent print processor? - correct answer ✔✔ -they locate and develop fingerprints and
may handle database entry
-chemistry and lab training needed
What is a latent fingerprint examiner? - correct answer ✔✔ -they classify prints, determine if
fingerprints are a match or not, and testify in court
How do fingerprints form? - correct answer ✔✔ -they start forming at 4 months and are
consistent throughout life. They are friction ridges
Where does the fingerprint impression come from? - correct answer ✔✔ -sweat
-sebum
-lipids
-foreign material
How do fingerprints stick? - correct answer ✔✔ sebum and sweat are secreted by your pores
and it sticks to the substrate when pressed
What foreign material could help a fingerprint stick? - correct answer ✔✔ -and sufficiently
viscous material
-blood
,-ink
-motor oil
-pizza grease
What are the three types of prints? - correct answer ✔✔ -patent
-latent
-impression/plastic
What are 10 prints used for? - correct answer ✔✔ used for comparison with unknowns
What are latent prints? - correct answer ✔✔ -invisible to the naked eye
-must be developed with chemicals or light
-porous, nonporous, and semi-porous substrates
What is dusting? - correct answer ✔✔ when powder is used to find fingerprints and it sticks to
fats and oils
During dusting, different colored powders are used for what? - correct answer ✔✔ different
substrates
What is dusting applied with and cleaned up with? - correct answer ✔✔ applied with a
fiberglass brush and cleaned up with camel hair
What kind of substrates is dusting used for? - correct answer ✔✔ nonporous and semi porous
substrates
What are the steps to lifting a print? - correct answer ✔✔ 1. photograph
, 2. press the lifting tape across the print
3.smooth tape flat
4. lift off the print
5. press it over the lift card
What kind of substrates is ninhydrin used on? - correct answer ✔✔ porous substrates (paper)
What is Ninhydrin? - correct answer ✔✔ It is a way to find fingerprints. It reacts with the amino
acids in a print to form "Ruhemann's Purple" and also works with faint prints in blood
What kind of substrate is Cyanoacrylate Fuming used on? - correct answer ✔✔ nonporous
substrates
What is Cyanoacrylate Fuming? - correct answer ✔✔ When fumes bind to fats in the presence
of water and binds to very small fingerprints. It forms a protective layer on the print
Superglue + Dye + ALS - correct answer ✔✔ These fingerprints can only be "lifted" through
photographs
What can you use to enhance blood prints? - correct answer ✔✔ -Leucocrystal Violet (reacts
with the hemoglobin)
-amido black (reacts with the proteins)
-Coomassie Blue
-Hungarian Red
What was fingerprinting in ancient times? - correct answer ✔✔ The Chinese used fingerprinting
in seals by 264 BCE
Exam 3 Comprehensive Study Notes
When is trace evidence formed? - correct answer ✔✔ generated when objects touch each other
and remains of material are left behind
What is a latent print processor? - correct answer ✔✔ -they locate and develop fingerprints and
may handle database entry
-chemistry and lab training needed
What is a latent fingerprint examiner? - correct answer ✔✔ -they classify prints, determine if
fingerprints are a match or not, and testify in court
How do fingerprints form? - correct answer ✔✔ -they start forming at 4 months and are
consistent throughout life. They are friction ridges
Where does the fingerprint impression come from? - correct answer ✔✔ -sweat
-sebum
-lipids
-foreign material
How do fingerprints stick? - correct answer ✔✔ sebum and sweat are secreted by your pores
and it sticks to the substrate when pressed
What foreign material could help a fingerprint stick? - correct answer ✔✔ -and sufficiently
viscous material
-blood
,-ink
-motor oil
-pizza grease
What are the three types of prints? - correct answer ✔✔ -patent
-latent
-impression/plastic
What are 10 prints used for? - correct answer ✔✔ used for comparison with unknowns
What are latent prints? - correct answer ✔✔ -invisible to the naked eye
-must be developed with chemicals or light
-porous, nonporous, and semi-porous substrates
What is dusting? - correct answer ✔✔ when powder is used to find fingerprints and it sticks to
fats and oils
During dusting, different colored powders are used for what? - correct answer ✔✔ different
substrates
What is dusting applied with and cleaned up with? - correct answer ✔✔ applied with a
fiberglass brush and cleaned up with camel hair
What kind of substrates is dusting used for? - correct answer ✔✔ nonporous and semi porous
substrates
What are the steps to lifting a print? - correct answer ✔✔ 1. photograph
, 2. press the lifting tape across the print
3.smooth tape flat
4. lift off the print
5. press it over the lift card
What kind of substrates is ninhydrin used on? - correct answer ✔✔ porous substrates (paper)
What is Ninhydrin? - correct answer ✔✔ It is a way to find fingerprints. It reacts with the amino
acids in a print to form "Ruhemann's Purple" and also works with faint prints in blood
What kind of substrate is Cyanoacrylate Fuming used on? - correct answer ✔✔ nonporous
substrates
What is Cyanoacrylate Fuming? - correct answer ✔✔ When fumes bind to fats in the presence
of water and binds to very small fingerprints. It forms a protective layer on the print
Superglue + Dye + ALS - correct answer ✔✔ These fingerprints can only be "lifted" through
photographs
What can you use to enhance blood prints? - correct answer ✔✔ -Leucocrystal Violet (reacts
with the hemoglobin)
-amido black (reacts with the proteins)
-Coomassie Blue
-Hungarian Red
What was fingerprinting in ancient times? - correct answer ✔✔ The Chinese used fingerprinting
in seals by 264 BCE
