Scientists at the Los Alamos National Laboratory have developed a novel method for detecting fingerprints based on the chemical elements present in fingerprint residue. The technique is called Micro-X-Ray Fluorescence (MXRF), and has the potential to help expand the use of fingerprinting as a forensic investigation tool. The technique detects fingerprints by an X-Ray analysis of the chemical residue left behind (salts, such as Sodium Chloride and Potassium Chloride, excreted in sweat). Current forensic techniques often involve a physical interaction with the print (treating the suspect area with powders, liquids, or vapors); so this X-Ray method is a superior one.

X-Ray images of fingerprints (Courtesy: Los Alamos National Laboratory)MXRF detects the elements (Sodium, Chlorine, Potassium, and others) present in the fingerprint. Many fingerprints leave a chemical trace behind, and it takes really small amounts for it to be detected by MXRF.
However, scientists assert that it is not a panacea, since some fingerprints will not contain enough chemicals to be seen. Also, bacteria/nature might destroy some fingerprints (especially if they are old). But MXRF does offer a non-invasive way of detecting a fingerprint, which leaves it pristine for other techniques, notably DNA extraction. It is also faster than other fingerprinting techniques, and therefore can be a useful tool since time is often the most important factor in solving any crime.