The reliability of fingerprint pore area in personal identification

Abstract

Reproducibility of third level fingerprint detail is important in personal identification. The effect of different substrates on the reproducibility of pore dimensions in inked reference fingerprints was investigated. Photomicrographs of reference prints were taken and pore area was measured repeatedly using appropriate software. Reproducibility of pore area was also studied in latent prints. Latent prints were deposited on chosen absorbent and non-absorbent surfaces and developed using Cyanoacrylate and Ninhydrin to determine pore area reproducibility. Photomicrographs of ridged skin were captured directly by focusing under microscope and pore area reproducibility in these images was studied. Live scans were also included in the study to see if pore area can be relied upon in live scans at 500ppi (pixels per inch). Results revealing best third level detail in inked prints were achieved by deposition onto a variety of non-absorbent substrates but inter-print variation indicated that pore area in inked prints deposited onto paper substrates cannot be used reliably in personal identification. In case of latent prints, variation was greater than normal acceptable limits suggesting that pore area is not reproducible in latent prints developed using Cyanoacrylate and Ninhydrin techniques. Results of direct microscopic images also showed too great inter-image variation which has further supported the unreliability of pore area as a tool in personal identification. Live scans at 500ppi did not prove to be useful in providing good pore detail for study. This study casts doubt on the use of pore area as a reliable identification tool in personal identification and suggests raising the scanning resolution to study pore detail in live scans.