Hot prints

Two students at Australia's University of Technology, Sydney have developed a new way to visualise fingerprints left on paper.

Adam Brown and Daniel Sommerville set out to create new reagents that would allow them to visualise fingerprints on paper, but during the process uncovered the simpler, safer and more economical method for developing the images.

Current methods for visualising fingerprints on paper are labour-intensive and time-consuming, using toxic dyes and chemicals to stain the fingerprints or make them fluorescent.

The method developed by the two students relies on the application of heat to the sample, with the fingerprint development accomplished in a matter of seconds.

'This was an interesting approach, as originally the aim was to make fingerprints coloured using chemicals, but the students noticed that the application of heat alone could actually develop fingerprints,' said Dr Brian Reedy, a senior lecturer and member of the Centre for Forensic Science in the Faculty of Science.

'An extensive literature survey and discussions with other researchers revealed that there had been little research done regarding the application of heat to fingerprints, as it had been considered impractical and inferior to other techniques.

'Our team refined the thermal technique, exposing fingerprints to hot air at temperatures of up to 300^oC for periods of 10 to 20 seconds, which produced well-defined images.

'We also observed that after shorter heating times, fluorescent prints could be observed.'

Dr Reedy believes the technique could lead to changes in how fingerprints are collected.

'By removing the need for dyes and chemicals, this method makes fingerprint development on paper-based materials much easier and safer, and the images are available much more quickly.

'It is promising as there is the potential to make portable fingerprint imaging devices, which could be used directly at a crime scene.

'There is also the scope for higher volumes of documents to be treated, something which usually doesn't occur with more time-consuming or expensive methods.'

The research has now been licensed to Foster & Freeman for commercialisation.

The company develops a wide range of scientific instruments for police and forensic laboratories across the world.