Latent fingermark pore area reproducibility

Quaternary phosphonium AIEgens nanoparticles as innovative agents for developing latent fingerprints

Quaternary phosphonium salts, a significant category of organophosphorus compounds, have garnered substantial attention from chemists due to their wide range of applications across various research areas. These compounds are utilized in organic synthesis, catalysis, medicinal chemistry, natural materials, and coordination chemistry. Their versatility and effectiveness in these fields make them valuable tools in scientific research. Despite their extensive use in various applications, the potential of quaternary phosphonium compounds as fluorescent agents for revealing latent fingerprints (LFPs) remains largely unexplored, presenting an exciting opportunity for further research and development in forensic science. In this study, we designed molecules that combine the aggregation-induced emission (AIE) chromophore with triphenylphosphine to create a series of novel AIE amphiphiles, namely TPP1, TPP2, and TPP3. Through precise adjustment of the carbon chain length between the phenoxy group and the terminal triphenylphosphine, we were able to finely tune the nanostructures and hydrophobicity of the materials. TPP3 emerged as the optimal candidate, possessing the ideal particle size and hydrophobicity to effectively bind to LFPs, thus enabling efficient fingerprint visualization with enhanced fluorescence upon aggregation. Our findings introduce an innovative approach to fingerprint visualization, offering high selectivity, superior imaging of level 3 structures, and long-term effectiveness (up to 30 days). Additionally, TPP3's outstanding performance in imaging level 3 structures of LFPs is beneficial for analyzing incomplete LFPs and identifying individuals. By significantly improving the detection and analysis of LFPs, this approach ensures more accurate and reliable identification, making it invaluable for forensic investigations and security measures. The adaptability of these compounds to various fingerprint surfaces highlights their potential in diverse practical applications, enhancing their utility in both forensic science and security fields. This versatility allows for precise fingerprint visualization across different scenarios, making them a critical tool for advancing biometric and security technologies.

Useless or used less? Poroscopy: The evidence of sweat pores

Poroscopy is the study of sweat pores present on the papillary ridges of the skin. This review paper aims to examine existing literature on poroscopy so that its relevance as a tool in personal identification can be established. Moreover, this paper aims to expound the various aspects of sweat pores as well as, highlight the contribution of poroscopy in latent, partial, and automated fingerprint matching. The relationship between sexual dimorphism, age, and sweat pores, effect of development technique and nature of surface on pore details, and use of sweat pores for liveness detection in biometric systems has also been explored. A review of all potentially relevant articles was conducted wherein, the non-relevant papers were excluded by screening their titles and abstracts following which, full-text review of all articles that met the inclusion criteria was carried out. The authors concluded that sweat pores present additional distinctive information for facilitating personal identification when used along with level 2 details. Furthermore, out of the various pore parameters namely, number, shape, size, inter-distance, position, and type, pore inter-distance was found to be most reliable.

Wet nitrocellulose membrane for the level 3 feature visualization of various latent fingerprints and gender determination

A facile and high-resolution enhancement of latent fingerprints (LFPs) has been developed by using a wet nitrocellulose (NC) membrane as a matrix under natural light. A clear fingerprint pattern was presented on the membrane after a fingertip touch owing to the difference in light transmittance between the ridge residues and the wet-NC-membrane background. Compared with conventional methods, this protocol can provide a higher resolution fingerprint image to extract level 3 details accurately. It is also compatible with commonly used fingerprint visualization techniques (magnetic ferric oxide powder and AgNO₃. The modified membrane could be more general to realize the high-resolution visualization of LFP transferred from various substrates, even independent of light projection. Due to the excellent feasibility and reproducibility of level 3 details extracted by the wet NC membrane, the frequency distribution of the distance between adjacent sweat pores (FDDasp) could be used to effectively distinguish the fragmentary fingerprints. Finally, the level 3 features of LFPs from females and males were conveniently extracted by the wet-NC-membrane method for gender identification. The statistical results indicated that females had a higher average sweat pore density (115/9 mm²) than males (84/9 mm²). Taken together, this approach provided a high-resolution, reproducible, and accurate imaging of LFPs, which shows great promise for forensic information analysis.

Recent Progress in Visualization and Analysis of Fingerprint Level 3 Features

Fingerprints provide sufficient and reliable discriminative characteristics which have been considered one of the most robust evidence for individualization. The limitation of current minutiae-based fingerprint technology seems to be solved with the development of level 3 features since they can offer additional information for problematic fingerprint recognition and even donor profiling. So far, tremendous efforts have been devoted to detecting and analysing the third-level details. This review summarizes the advances in level 3 details with an emphasis on their reliability assessment, visualization methods based on physical interaction, residue-response, mass spectrometry and electrochemical techniques, as well as the potentiality for individualization, donor profiling and even other application scenarios. In the end, we also give a personal perspective on the future direction and the remaining challenges in the third-level-detail-related field. We believe that the new exciting progress is expected in the development of level 3 detail detection and analysis with continued interest and attention to this field.

Reproducibility and reliability of fingerprint microfeatures: Effect of immersing hand in water at different temperatures

Poroscopy is the specialized study of sweat pores found on the papillary ridges of the skin. However, the science of poroscopy is not being used to its full potential. The present study was conducted with the goal to assess the effect of immersing hand in water at various temperatures i.e., room temperature (20-30 °C), hot temperature (40-50 °C), and cold temperature (0-10 °C), for 1, 5 and 10 min, on the reproducibility of pore microfeatures namely, area, inter-distance, and angle, in an attempt to demonstrate their reliability in fingerprint matching. As far as the authors are aware, no prior research has attempted to evaluate the impact of immersing hand in water, at different temperatures, on the reproducibility of third level details. Statistical analysis of data revealed that pore inter-distance and angle were reproducible in nature thereby, highlighting their significance in fingerprint matching.

Reproducibility of fingerprint microfeatures

Background

Poroscopy, as a means of personal identification, is largely unexplored. The present study aims at assessing the reproducibility of fingerprint microfeatures namely, pore area, inter-distance, and angle, in fingerprints obtained on two surfaces namely, glass and sticky side of adhesive tape, for a period of ten consecutive days. As far as the authors are aware, no prior research has attempted to evaluate pore parameters on sticky side of adhesive tape.

Methods

Plain-inked fingerprints of the left thumb, right thumb, and right index finger were collected on two surfaces namely, glass and sticky side of adhesive tape (using two methods) for ten consecutive days. Photomicrographs were captured and four pores, lying on the same ridge and having clear well-defined margins, were selected from the central region of each print. These specific sweat pores were used to measure the pore area, inter-distance, and angle using Image Pro® Software. Data were analyzed using Statistical Product and Service Solutions (SPSS) software version 16. One way analysis of variance (ANOVA) was carried out using “area,” “length,” and “angle” as the dependent variables.

Results

Results obtained depict pore area, inter-distance, and angle to be significant (p<0.001), on all 10 days for both the surfaces. In terms of quality, better pore details were depicted by fingerprints obtained on the sticky side of adhesive tape (using procedure (iii), wherein the sticky side of adhesive tape was pressed against the inked thumb of the participant). Furthermore, the pore area was found to be non-reproducible while the pore inter-distance and angle were found to be reliable and reproducible in nature.

Conclusions

Crime scene fingerprints should be first matched with specimen fingerprints on the basis of ridge characteristics. However, on occasions when sufficient number of ridge characteristics are not available for comparison, sweat pores should be employed. This study highlights the reproducibility and reliability of pore inter-distance and angle and encourages their use in fingerprint matching.

Fast and quantitative analysis of level 3 details for latent fingerprints

Level 3 details play essential roles in practical latent fingerprint (LFP) identification. To reliably extract reproducible and identifiable level 3 features, high-resolution images of fingerprints with adequate quality are required. Conventional methods for acquiring level 3 details often involve specific pretreatment, intricate peripheral, leading to time-consuming analysis. Herein, we simply used water to develop the sebaceous LFPs deposited on nitrocellulose (NC) membranes with only one step, and then the high-resolution (2048 pixels per inch) optical micrographs were captured to reflect the live fingertip with high fidelity. From the pictures, level 3 features, including all dimensional attributes of the ridges and pores such as number, size, location, shape, and edge contour can be extracted accurately and reproducibly. Among them, qualitative features (the structures of ridge edges) and several quantitative characteristics (the number and the relative location of sweat pores) exhibit good reproducibility. Remarkably, we proposed a new parameter termed "frequency distribution of the distance between adjacent sweat pores", short form "FDDasp", which was further proved highly identifiable in different individuals, enabling the successful distinguishment between two fragmentary fingerprints with similar level 2 structures. We believe that this methodology provides a fast and quantitative analytical paradigm for latent fingerprint identification at level 3 details.

The permanence of friction ridge skin and persistence of friction ridge skin and impressions: A comprehensive review and new results

This study addresses the permanence and persistence of friction ridges and the persistence of impressions made from these friction ridges over months and years. Permanence is the unchanging presence and appearance of friction ridge arrangements and their attributes between recurring observations of the skin. Permanence was evaluated from direct photographs of fingers collected over a period of 30-45 days (covering one or more skin regeneration cycles) as well as after 8 or more years had elapsed. Persistence embodies the operational concept of whether or not a pair of images displays sufficient similarity upon which to base an informed decision that they were made by the same finger, while acknowledging certain dissimilarities or distortions due to friction ridge physiology, image capture, matrix, substrate, and applied pressure. Persistence applies to both friction ridge skin and impressions made from these friction ridges. Permanence and persistence of skin were assessed from direct photographs of fingers taken two months apart and from finger photographs separated by an interval of at least 8 years. Permanence and persistence were also assessed from impressions taken over 4 months, as well as those separated by 8-53 years. Variability due to capture method was assessed by using four image capture methods over a four month period: direct photography of fingers, impressions captured by ink, holographic imaging, and live scan. Qualified latent fingerprint examiners assessed all changes observed over time, as well as any limitations imposed by capture method. The practice of comparison and identification of fingerprint impressions was upheld, as was the prevailing use of the word persistence to describe stability of friction ridges. All photographs and impressions of the same finger were identifiable as originating from the same source. Within all the periods of observation, level 1 detail was permanent and persistent. Persistence, but not permanence, was supported for level 2 detail. Notably, the small changes observed were only in appearance; there were no changes in the presence of new, or absence of existing, minutiae. Level 3 details of ridge edge shape and pore presence were neither permanent nor persistent. Ridge width was permanent and persistent. Incipient ridges were neither permanent nor persistent.

Sweat pore mapping using a fluorescein–polymer composite film for fingerprint analysis

A simple but efficient sweat pore mapping method based on a fluorescein–PVP composite film was developed for fingerprint analysis.