Fingerprints, as most of us know, are composed of whorls, loops, and arches. But keep zooming in, and you'll find tiny, tiny sweat pores arranged in patterns equally unique. Scientists in Korea have found a new way to map those pores that could help identify decade-old fingerprint fragments.
The sweaty creatures they are, humans leave little imprints on everything we touch. And the imprints last: the dried remnants of sweat on paper 10 years old could still reflect the pattern of pores on our fingertips today, according to Jong-Man Kim of South Korea's Hanyang University. Just 20 to 40 of the pores can be used to identify a person.
Kim's team has found an easy way to create precise maps of sweat pores with a polymer that changes color with water. Press a finger lightly onto a blue polymer-coated film, and red dots of sweat immediately appear. This map could then be compared against fingerprint fragments that might be too small to analyse traditionally.
"Unfortunately, these pore dot images have been for the most part neglected owing to the fact that rapid, reliable and affordable ﬁngertip pore mapping technologies have not been developed," write the authors in their paper. Of the three levels of fingerprint features, statistical models tend to stick to the first two.
It's worth noting that behind every technology is the infrastructure supporting its implementation—in this case, databases, labs, automated software to find statistical matches for fingerprints. Fingerprint analysts have long been aware of sweat pores, but they haven't quite had the infrastructure to systematically analyze them. That could change, so sweaty-handed criminals beware. [Nature Communications via Science News]
Image credits. Top: Fluorescence sweat pore images on a fingertip. Kim et al. Bottom: Fingerprint features via Jain and Chen