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Enhancement of latent fingermarks found at crime scenes can be crucial to criminal investigations. The performance of ninhydrin analogues 1,2-indanedione (IND/Zn) and 1,8-diazafluoren-9-one (DFO) used in laboratories for the enhancement of latent fingermarks on porous substrates were compared for operational use. The visualisation of enhanced latent fingermarks on seven substrates commonly encountered in local crimes - plain A4 paper, glossy magazine, paper magazine, brown envelopes, white envelopes, cardboard, and joss paper were assessed using fingermarks deposits from seven donors. Fingermarks were aged under both indoor and outdoor conditions as well as over different periods of time. Our results show that IND/Zn consistently produced fingermarks of superior quality and contrast to DFO across the different donors, substrates and time periods. IND/Zn also appears to be more sensitive compared to DFO.

1,2-indanedione (1,2-IND) and 1,8-diazafluoren-9-one (DFO) are used in the forensic field to enhance latent fingerprints deposited on porous surfaces due to the formation of fluorescent products by reacting with the amino acids present in the papillary exudate. The study was carried out in collaboration with the Fingerprints and Photography Section of the Carabinieri Scientific Investigation Department (RIS) of Rome, in which laboratories, until now, DFO has been the most used because of its excellent enhancing properties, even if it is more expensive and relatively toxic in comparison with the 1,2-IND. The aim of this work was then to evaluate and to compare the effectiveness of three solutions of 1,2-IND in different formulations and a DFO solution employed as single enhancing treatments, in order to assess whether it was possible to replace a reagent with the other obtaining equally satisfying results. In this case, white office paper was selected as deposit surface since it also permitted one to observe those reaction products that appear visible to a naked eye. Beside to a qualitative study of the visual characteristic of the enhanced fingerprints, further quantitative studies were conducted on the intensity of fluorescence of the products and on the consumption of amino acids during the reaction. The analyses, which at first were conducted on standard samples, were then repeated on real samples to validate the results obtained. The DFO confirmed its excellent enhancement properties, but also one of the three solutions of 1,2-IND showed comparable properties in terms of enhanced fingerprint definition and stability over time from the completion of a crime. As a result, we proved that a selected 1,2-IND formulation may replace with satisfactory achievements the DFO solution currently employed, providing also advantages from the point of view of safety and cost savings.

The near infrared (NIR) spectral region could offer advantages over the visible region in the detection of latent fingermarks due to the enhanced contrast between the background and the print. In this present paper, this spectral range of the electromagnetic spectrum was explored in order to study the possibility to make feasible the inspection of forensic evidences when the substrate is represented by the thermal paper, which is one of the most extensively used porous surfaces for printing receipts. We successfully applied the method to thermal paper treated with several kinds of amino acid sensitive reagents. We demonstrated that, even if the treatments could cause a dark stain over the latent fingermarks, by exploiting the luminescence of thermal paper in the NIR window we were able to create a contrast otherwise impossible in the visible region.

The abilities of two natural products, genipin and lawsone, to enhance blood contaminated fingermarks on papers of various porosities and colour were investigated and compared to the routinely used amino acid reagents, ninhydrin and 1,8-diazafluoren-9-one (DFO). Fingermarks in blood were deposited as a split depletion series on various paper types and colours for ageing periods of 6 weeks, 4 weeks, 2 weeks and 1 week before enhancement. The developed marks were observed under different lighting conditions, recorded and graded by way of attributing quantitative data to each series. Results indicated that while genipin showed some potential as a reagent for the enhancement of latent fingermarks, it displayed no suitability for the enhancement of fingermarks in blood on paper. Lawsone also failed to successfully enhance either type of fingermark. Upon comparison of the results with those of ninhydrin and DFO it was found that ninhydrin displayed the highest success rate of development of these marks.

1,2-Indanedione has been extensively researched since the discovery of its fluorogenic reaction with amino acids in 1997 by Joullie et al. [1]. This current study compares the development of fingermarks on used train tickets by the three leading reagents for amino acids-ninhydrin, DFO and 1,2-indanedione. The train tickets are ideal for the task due to their high abundance and frequent use by a diverse population. However, their unique double-layer composition of a cellulose-based regular paper on one side and a thermally sensitive layer on the other requires an adjustment of the traditional development procedures. Heat, which is normally applied after dipping the specimens in the reagents solutions, had to be avoided due to darkening of the sensitive thermal layer. Instead, it has been replaced by air-drying in a fume-hood 24h prior to the recording of the results. Three groups, each containing 500 used train tickets had been treated by each of the three reagents. The results were expressed in terms of percentage of both comparable and partial fingermarks. In this study we controlled neither the quality of the fingerprint donors nor the conditions under which the latent fingermarks had been deposited or stored. However, the large number of similar exhibits which are randomly chosen allows tentative conclusions on the potential of each reagent, hence, a new criterion for the potential of fingermark development (PFD) is proposed. The PFD combines all the partial fingermarks and identifiable fingermarks (graded 1 and 2) thus, highlighting the sensitivity of the reagents. In this work, the superiority of 1,2-indanedione is demonstrated using both the traditional comparison tests as well as the suggested "PFD".

1,2-Indanedione is an emerging fingermark reagent used on porous surfaces. The general consensus is that this reagent is at least as sensitive as DFO, with some research showing higher sensitivity for 1,2-indanedione as opposed to DFO. However, a number of discrepancies existed in the literature as to which formulation and which development procedure produces optimal results. This project set out to investigate the best formulation and development procedure under Australian conditions, encompassing all published recommendations as well as some novel approaches. 1,2-Indanedione formulations were compared with respect to initial colour, fluorescence, concentration of reagent, acetic acid concentration, and the effect of different carrier solvents. Numerous development conditions were investigated, including a conventional oven, a heat press and humidity. Further enhancement using metal salt treatment and liquid nitrogen was also evaluated. The heat press set at 165 °C for 10 s proved to give the best initial colour and most intense luminescence. Secondary metal salt treatment improved initial colour and luminescence. The Polilight, the VSC 2000, and the Condor Chemical Imaging macroscope have been used to detect the fingerprints developed with 1,2-indanedione on a variety of high- and low-quality porous and semi-porous surfaces, with impressive results overall. Laboratory and field tests were conducted to compare 1,2-indanedione with DFO and ninhydrin as well as to investigate the position of 1,2-indanedione in the sequence of reagents for fingermark detection on porous surfaces. Overall, 1,2-indanedione proved to be a viable alternative to traditional methods for the detection of fingermarks on porous surfaces, with more fingermarks being developed using this reagent on real samples than both DFO and ninhydrin and a combination of the two reagents. © 2006.

© 2015 Elsevier Ireland Ltd. Most spectroscopic studies of the reaction products formed by ninhydrin, 1,2-indanedione-zinc (Ind-Zn) and 1,8-diazafluoren-9-one (DFO) when reacted with amino acids or latent fingermarks on paper substrates are focused on visible absorption or luminescence spectroscopy. In addition, structural elucidation studies are typically limited to solution-based mass spectrometry or liquid nuclear magnetic resonance (NMR) spectroscopy, which does not provide an accurate representation of the fingermark development process on common paper substrates. The research presented in this article demonstrates that solid-state carbon-13 magic angle spinning NMR (13C-MAS-NMR) is a technique that can not only be utilised for structural studies of fingermark enhancement reagents, but is a promising technique for characterising the effect of paper chemistry on fingermark deposition and enhancement. The latter opens up a research area that has been under-explored to date but has the potential to improve our understanding of how fingermark secretions and enhancement reagents interact with paper substrates.

A new method for improved development of latent fingermarks on thermal paper by 1,8-diazafluoren-9-one (DFO) treatment is described. Compared with conventional DFO solution, the mixed solution of DFO/PVP (polyvinylpyrrolidone) described here reduces black background staining without removing the thermosensitive layer and develops fingermarks by the reaction of DFO with amino acid deposited on the thermal paper's surface. An advantage of this approach is that the developed fluorescent fingermarks have high contrast and can be observed and photographed when excited in the 515 nm region and observed through an orange-red barrier long-pass filter with no background coloration. In addition, the method reported here does not involve any pre- or post treatment of the substrate and exhibits high sensitivity with good stability. Experimental results showed that the method was able to develop very old fingermarks, up to 154 days old, demonstrating the feasibility of using the method to develop identifiable latent fingermarks operationally. Furthermore, we extended our experiments to various types of thermal papers. Notably, this method exhibits several very attractive features, namely time saving, simple procedures, inexpensive, convenient operation, and PVP is non-toxic and reasonably priced. Finally, in this study an attempt has been made to explain the reaction mechanism of the process and the effects of PVP.

Continual reports of illicit trafficking incidents involving radioactive materials have prompted authorities to consider the likelihood of forensic evidence being exposed to radiation. In this study, we investigated the ability to recover latent fingermark evidence from a variety of substrates that were exposed to ionizing radiation. Fingermarks deposited on common surfaces, including aluminum, glass, office paper, and plastic, were exposed to doses ranging from 1 to 1000 kGy, in an effort to simulate realistic situations where evidence is exposed to significant doses of radiation from sources used in a criminal act. The fingermarks were processed using routine fingermark detection techniques. With the exception of glass and aluminum substrates, radiolysis had a considerable effect on the quality of the developed fingermarks. The damage to ridge characteristics can, in part, be attributed to chemical interactions between the substrate and the components of the fingermark secretions that react with the detection reagents. © 2009 American Academy of Forensic Sciences.