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fingerprints
| Question | Answer |
|---|---|
| Finger Prints with a method for classification of fingerprints written by english scientist | Francis Galton |
| Indian police officer who proposed modified classification system (Henry System) | Sir Edward Henry |
| English physician who published in Nature suggesting use of fingerprints for identification | Dr Henry Faulds |
| When did US start using fingerprints | 1901 |
| National fingerprint file set up in American FBI | 1930 |
| formed in dermal papilae, formed by contact of friction ridges on hands feet or lips with an object | fingerprint |
| how are prints left | body is constantly having water/oils through pores |
| what kind of evidence are fingerprints | individual evidence |
| how many prints are required for a match | 14-16 prints |
| what is minutiae | the number, location and shape of specific ridge characteristics |
| How deep does the damage need to be to change the fingerprints | 2 mm below surface of skin for permanent damage |
| What permits fingerprints to be systematically classified and broken down | the general ridge patterns |
| What is assumed to stop fingerprints but is false | wearing gloves |
| What are the 3 basic patterns | Loops Whorls and Arches |
| Population of Loops | 60-65% |
| Population of Whorls | 30-35% |
| Population of Arches | 5% |
| Common african pattern | frequent arches |
| Common caucasian pattern | frequent loops |
| Common asian pattern | fairly high frequency of whorls |
| Loop characteristics | 1+ ridges entering from one side, re curving and exiting from same side |
| Loop that opens toward little finger | Ulnar loop |
| Loop that opens toward thumb | Radial loop |
| Different Types of Whorl | Plain, central pocket, double loop, and accidental |
| made up of 2 loops | double loop |
| at least 1 ridge that makes a complete circle | plain/central pocket |
| pattern not covered by other categories | accidental |
| What loop pattern has one or more deltas/core | Whorls |
| What loop pattern has friction ridges that enters on one side of the finger and cross to the other side while rising upward in the middle | Arch |
| What loop pattern has no type lines, deltas or cores | Arch |
| 2 types of Arches | Plain - weave like Tented - Center rises to aspike |
| how to individualize fingerprints | ridge characteristics/minutia points |
| 30 dif minutiae points , what are the most common | Ridge ending + bifurcation (fork) |
| Primary classification, 10 finger system, 1+ (sum of whorled, even finger value) / 1+(sum of whorled, odd finger value)= primary group ration | Henry system |
| Scanning device turns print 3D, makes thousands of comparison per second | AFIS |
| Lip (cigarettes/napkins) and Ear (windows/doors/walls) | Other Useful prints |
| Reticular, Vertical,Intersected, Branched, Partial Vertical | Lip print patterns |
| Latent, Visible, Plastic | Types of Prints |
| invisible to naked eye, oils left behind are dusted and lifted, most common | Latent |
| When finger was in contact with colored material (ink/paint blood) | Visible |
| Impressions in soft material (wax/soap) | Plastic |
| Photography, Dusting, Alternate light sources, Chemical Method | Ways to show Prints |
| Using a fine powder to reveal the trace of oil and sweat, used on glass/mirrors, | Dusting |
| Aluminum dust, carbon black, luminescent powder, magnetic powder | Different types of dusting powders |
| grey and highly visible on dark and mirrored surfaces | Aluminum Dust |
| White surfaces | Carbon Black |
| fluoresce under ultraviolet light | Luminescent |
| Used with powder, powders that glow in the dark, using fabric softener to brighten | Alternate Light Sources |
| Used for porous surfaces (paper/cloth) or textured surfaces (weapon handle). Ex: ninhydrin (#1 for paper) | Chemical Methods |
| Used for Zodiac Killer, colorless compound spray and turn purple, appeears with 1-2 hrs, weaker prints 24-48 hrs. Used to develop latent prints on paper as old as 15 yrs | Ninhydrin Method |
| Object place in chamber with crystals of iodine, prints appear brown, temporary and will fade so photo | Iodine Fuming |
| Gets sprayed on to salt/sweat and then expose to UV it will turn a gray/black color | Silver Nitrate |
| common in textured samples, reacts with printts/sticks to them and makes a 3d mold to dust | Superglue Fuming |
| Very sensitive, sprayed on blood and it stains the blood blue/black color | Amido Black |
| they individualise, never change and can be categorized | Why can we use fingerprints in forensics |
| 3 principles | individual evidence, will never change, the ridge patterns make it systematically classified. |
| what determines individuality | the number, location and shape of specific ridge characteristics |
Created by:
evamarygarcia
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