• Analytical Science and Technology
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• v.32 no.5
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• pp.196-209
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• 2019

As a traditional method to apply fingerprint powder, brush method ("dusting") can create a risk to the health of crime scene investigators due to the inhalation toxicity of harmful and fine powders. Therefore, as a new method of applying powders, we tried to evaluate the potential of a chamber method for the development of latent fingerprint using fans in a closed chamber with a fixed capacity that can prevent the powders from being blown outside and exposed to the users, by comparing with the development results of the conventional brush method. Fingerprints on glass and plastic (PET) were extracted with black powder and green fluorescent powder, and the sharpness and minutiae of the developed fingerprints were compared for each method. The results of the black powder showed similar results, but the effect of the chamber method was slightly decreased when the green fluorescent powder was used. In order to improve the development with the green fluorescent powder, the mixture (50 : 50) of the fluorescent powder with the silica gel was tested and the results were similar to those of the brush method. It is expected that the chamber method has a high potential as a new powder application method considering the health of the crime scene investigator after fine tuning of development conditions with additional studies.

• Analytical Science and Technology
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• v.29 no.6
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• pp.283-292
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• 2016

Conventional fingerprint powders used during crime scene investigations pose potential health hazards. Thus, multiple natural replacement powders, including squid ink powder, indigo and rice powder were used to develop (visualize) latent fingerprints on non-porous surfaces (e.g., glass, plastic and tile). Fingerprints developed using the natural powders were compared using the Automatic Fingerprint Identification System (AFIS) with those developed with traditional black powder. The peak areas of ridges were also compared using densitometric image analyses. Collectively, objective and quantitative evaluation methods were developed. The effectiveness of natural powders varied depending on the surface but, in general, squid ink powder performed well on most surfaces. Indigo powder performed well on tile surfaces, while rice powder performed well on glass surfaces. Plastic was the most difficult surface from which to develop fingerprints. Image analysis using Field Emission Scanning Electron Microscopy (SEM) demonstrated the importance of the size and shape of natural powder particles to properly adhere to the ridges. Although densitometric image analyses did not correlate the number of minutiae and ridge peak areas, an unbiased, objective evaluation method would be possible using image analyses with a reference image. Additional experimentation will yield safe and cost-effective natural powders with which adequate fingerprint development can be performed.