Fingerprinting in the Digital Age Catherine Myers Independent Research Advisor: Gary Hauptmann...
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Transcript of Fingerprinting in the Digital Age Catherine Myers Independent Research Advisor: Gary Hauptmann...
Fingerprinting in the Digital Age
Catherine MyersIndependent Research
Advisor: Gary Hauptmann
Forensic Analyst
Baltimore County Crime Lab
What is a Fingerprint?
• Ridges and furrows developed by dermal papillae
• Skin secretions• Invisible deposits• Latent vs. patent
Dermal papillae
Sebaceous gland
Eccrine sweat pore
History of Fingerprinting
• Evidence of fingerprint use in ancient civilizations• Sir Edward Henry made first classification system • First fingerprint bureau in 1901
Loop Whorl Arch
Collecting Fingerprint Evidence
• Method depends on surface in question– Porous v. nonporous– Light v. dark
• Dusting
• Fuming
• Chemical development
Dusting Methods
• Powder: used on metal, glass and wood– Black or white– Fluorescent
• Magnetic: used on more porous surfaces like paper
Cyanoacrylate Fuming
• Superglue placed in sealed container
• Heated to approx. 120o
• Fumes evaporate• Cyanoacrylate adheres to
solid deposits of fingerprint• View under UV light or dye
with colored stain
Ninhydrin Development• Used on paper• Paper is submersed in ninydrin, allowed to dry• Evidence is placed in a warm, humid
environment• Ninhydrin reacts with amino acids in fingerprint
residue to form Ruhemann’s purple
Digital Enhancement
• Digital prints not as detailed as silver-developed prints
• Adobe Photoshop– Color balance– Brightness– Contrast– “Dodging and Burning”
EvidenceHow to Ensure that Evidence is
Admissible in Court
• “If this is a digital image, has it been enhanced or is this the original capture with no changes to it? If it’s been enhanced, I want you to show me what you did and tell me what your training is. And did you go out of your area of expertise to do this? (McRoberts)”
• Record of camera, lens, shutter speed, illumination, camera position, and distance and angle from an object
• Audit trail to document changes made
More Safeguards
• Original photograph should be
saved separately
• Changes should be directly reproducible
• Chain of custody should be documented and preserved
SourcesAll photos obtained from www.google.com/images
Berry, John, and David A Stoney. "History and Development of Fingerprinting."Advances in Fingerprint Technology. Ed. Henry C Lee and R E Gaensslen. 2nd ed. N.p.: CRC Press, 2001. 1-41.
Lee, Henry C, and R E Gaensslen. "Methods of Latent Fingerprint Development." Advances in Fingerprint Technology. 2nd ed. N.p.: CRC Press, 2001. 105-176. McRoberts, Flynn, and Steve Mills. "Digitized Prints can Point Finger at the Innocent." Chicago Tribune 3 Jan. 2005. 19 Dec. 2006 <http://www.truthinjustice.org/digitized-prints.htm>.
O'Connor, Tom. Fingerprints and Trace Evidence. 26 Dec. 2004. North Carolina Wesleyan College. 14 Nov. 2006 <http://faculty.ncwc.edu/toconnor/315/315lect05.htm>.
Prabahakar, Salir, and Anil Jain. "Fingerprint Identification." Biometrics Research. Michigan State University. 2 Nov. 2006 <http://biometrics.cse.msu.edu/fingerprint.html>.
Ramotowski, Robert S. "Composition of Latent Print Residue." Advances in Fingerprint Technology. Ed. Henry C Lee and R E Gaensslen. 2nd ed. N.p.: CRC Press, 2001. 63-04. Reis, George. Digital Image Integrity. 2004. Adobe. 19 Dec. 2006<http://www.adobe.com/digitalimag/pdfs/digital_image_integrity.pdf>.
Scientific Working Group on Imaging Technologies. Vers. 1.1. Feb. 2001. Florida Division of the International Association for Indentification. 19 Dec. 2006 <http://www.fdiai.org/images/SWGIT%20guidelines.pdf>.