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Monday, April 4, 2005

The purpose of the Detail is to help keep you informed of the current state of affairs in the latent print community, to provide an avenue to circulate original fingerprint-related articles, and to announce important events as they happen in our field.

Breaking NEWz you can UzE...
compiled by Jon Stimac

AFIS Technology Moves From the Lab to ID Programs SECURE ID NEWS, VA - Mar 31, 2005 ...though it doesn’t work exactly as it appears on TV, AFIS technology is very real and it has impacts beyond law enforcement...

Car Theft Gang Steals Man's Finger AGENCE FRANCE-PRESSE - Mar 31, 2005 ...criminals chopped off the tip of a man's finger to override a security feature that required his fingerprint to start his car...

Fingerprints Questioned in Heist Trial   NEWS CHANNEL, DE - Mar 29, 2005 ...attorneys are hoping to raise enough doubt about the accuracy of fingerprints to acquit bank robbery charges...

Lab Finds Elusive Fingerprints   ALBUQUERQUE TRIBUNE, NM - Mar 28, 2005 technique sees fingerprints on surfaces where they are virtually invisible using other techniques...


Last week, we looked at the use of gel lifters to lift latent prints from latex gloves.  This week we look at a press release from Los Alamos National Laboratory regarding a new latent print visualization technique that could hold new promise for non-destructive latent print recovery in the fingerprint discipline.  With a combination of this technique and DNA extraction, the best of both worlds could be achieved using the same impression.


Researchers Develop Fingerprint Detection Technology

LOS ALAMOS, N.M., March 21, 2005 – University of California scientists working at Los Alamos National Laboratory have developed a novel method for detecting fingerprints based on the chemical elements present in fingerprint residue. Known as micro-X-ray fluorescence, or MXRF, the technique has the potential to help expand the use of fingerprinting as a forensic investigation tool.

University of California scientists working at Los Alamos National Laboratory have developed a novel method for detecting fingerprints based on the chemical elements present in fingerprint residue. (Image courtesy of Los Alamos National Laboratory)

In research presented last week at the 229th national meeting of the American Chemical Society in San Diego, Calif., Los Alamos scientist Christopher Worley describes the detection of fingerprints based on elemental composition using micro-X-ray fluorescence showing how the salts, such as sodium chloride and potassium chloride, excreted in sweat are sometimes present in detectable quantities in human fingerprints.

MXRF actually detects the sodium, potassium and chlorine elements present in those salts, as well as many other elements, if they are present. The elements are detected as a function of their location on a surface, making it possible to "see" a fingerprint where the salts have been deposited in the patterns of fingerprints, the lines called friction ridges by forensic scientists.

The technique has several advantages over traditional fingerprint detection methods that involve treating the suspect area with powders, liquids, or vapors in order to add color to the fingerprint so that it can be easily seen and photographed. Using this technique, known as contrast enhancement, it is sometimes difficult to detect fingerprints present on certain substances, such as multicolored backgrounds, fibrous papers and textiles, wood, leather, plastic, adhesives and human skin. Children's fingerprints are particularly difficult to detect due to the absence of sebum, an oily substance on the skin that is secreted by the sebaceous glands, which captures the contrast enhancing agents. Also, coloring a fingerprint with traditional contrast enhancement methods can be an arduous process that sometimes yields only limited success.

Worley warns that MXRF is not a panacea for detecting all fingerprints, since some fingerprints will not contain enough detectable elements to be "seen". However, it is envisioned as a viable companion to the use of traditional contrast enhancement techniques at crime scenes, since it does not require any chemical treatment steps, which are not only time consuming, but can permanently alter the evidence. Since MXRF is noninvasive, a fingerprint analyzed by the method is left pristine for examination by other methods like DNA extraction.

In addition to Worley, the MXRF development team includes Sara S. Wiltshire, Thomasin C. Miller, George J. Havrilla and Vahid Majidi.


I will try to post additional information and images if possible if I can track them down.  The article will appear soon in the Journal of Forensic Sciences.

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Have a GREAT week!