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Cultivating Methods to Enhance the Quality of Aged Fingerprints Developed by Cyanoacrylate Fuming

NCJ Number
Date Published
November 2009
27 pages
The experiments conducted in this project examined the molecular-level processes that impact the superglue (cyanoacrylate) fuming of a latent fingerprint, so as to provide fundamental information that can be used by forensic scientists to optimize the fuming process.
The experiments were designed to reveal the role of water vapor in the chamber on the development process by fuming, to correlate the changes that occur in a latent print with aging to the processes that occur during the development of aged latent prints, and to understand the role of temperature on the print fuming process. The results indicate that the importance of humidity in the fuming of latent fingermarks comes from its role as a solvation agent for the initiators of the polymerization, creating an accessible solvated ion-pair rather than the less reactive tightly bound ion-pair. It was also found that aging resulted in ultraviolet (UV) degradation processes that decreased the pH of the fingermark, inhibiting the polymerization of ethyl cyanoacrylate (ECA) that is required to fume effectively a latent print. Fingermarks with less exposure to UV radiation will provide better prints. In examining the effect of temperature on the quality and amount of polymer formed on a fumed print, the experiment showed that lower temperatures provide more polymer and better quality prints. Lowering the temperature improved the rate of ECA polymerization, thus enhancing the efficiency and quality of fumed latent prints. This report advises that although these research results provide additional insight into the molecular-level details of the superglue fuming of fingermarks, they do not yet provide explicit protocols for improving the quality of latent fingerprints in the field; however, the findings can provide the information from which to design such protocols. Further research is required to fine-tune and test such protocols. 10 figures, 1 table, and 29 references

Date Published: November 1, 2009