Fingermarks have been used for centuries as a means of determining an individual’s identity and fabrics have long been considered a difficult substrate from which to visualise and collect fingermarks. This study mainly concentrated on vacuum metal deposition (VMD) and cyanoacrylate fuming (CAF), to ascertain whether these methods could visualise planted marks and consequently be used in the examination of clothing from assault cases. Nine different fabrics: cotton, polycotton, polyester, nylon, nylon-Lycra, satin, silk, rayon and linen along with fifteen donors ranging in age, sex and ability to leave fingermarks were used during this work. The donors were previously tested on paper to determine their propensity to leave fingermarks, which gave an indication as to their donor ability level – poor, medium or good. The samples were collected and processed with the appropriate technique after a determined time interval, generally, 1, 2, 3, 4, 5, 6, 7, 14, 21 and 28 days, however this was altered for some of the trials. From the results, it was found that both VMD and CAF did visualise marks and ridge detail from latent fingermarks. VMD was found to be the most suitable technique for development of fingermarks on fabric, with gold + zinc VMD best for light coloured fabrics and silver VMD for dark. CAF also visualised several identifiable marks, even with the problems of background fluorescence from the basic yellow 40 (BY40) dye used to visualise the cyanoacrylate (CA) polymer. Generally, it appears that the smoother fabrics with a tighter weave, such as nylon and silk allowed the visualisation of more detail than rougher and/or looser weave fabrics such as cotton and linen. The latter tended only to show empty marks or marks, which gave indications of where the fabric had been touched. However, fabrics that did show marks, even if not suitable for identification, could still give information as to the sequence of events that may have occurred during an assault as well as identifying an area to tape for DNA. It was determined that it was possible to collect DNA from VMD visualised marks which led to partial and full profiles of those who touched and grabbed the test swatches or items of clothing tested. Though both VMD and CAF were affected by the addition of water to the surface of the fabrics being processed, marks and ridge detail were still detected, though CAF was less effective than VMD. With sequential treatment, it appears that the optimum sequence is VMD followed by CAF, due to enhancement of contrast between the metal deposits and BY40 yellow stained background. CAF then VMD only led to extra detail being observed on nylon-Lycra. There was limited success with 1,8-diaza-9-fluorenone (DFO), small particle reagent (SPR), ninhydrin, fluorescent powders or the sputter coater for alternative VMD metals. The production of nanoparticles was unsuccessful; so no fingermark visualisation was attempted. Finally, the issue of ridge detail being obscured by the fabric weave may have been resolved by the use of IR photography or FFT processing. In conclusion, both VMD and CAF are viable processes for the development of fingermark and palm detail on fabric, clothing and textiles. It must be considered however that the donor and fabric being processed greatly affected the level of detail visualised. However, even if ridge detail is not visualised, any marks that are present could indicate a sequence of events or act as an area to target for DNA profiling.

This study investigated the use of UV-visible spectral imaging for the location and enhancement of substances of forensic interest using targeted approaches based on the spectrum of the substance. Spectral enhancement procedures were developed for blood with and without chemical enhancement, and for latent fingermarks after chemical enhancement. Focus was on substances whose spectrum exhibited a steep change in absorbance or fluorescence over a small wavelength range. Substances with such spectral features were able to be enhanced using arithmetic combinations of two or three spectral images taken at wavelengths near the steep spectral feature. Some enhancement reagents do not react to produce a product with a steep spectral feature suitable for photographic enhancement. In such cases reagents that compliment spectral imaging can be developed. A tridentate ligand for iron(II), BBIDMAPP, which forms a complex with a narrow intense charge-transfer band, was synthesised and was used to visualise muddy shoemarks. UV-visible spectral imaging systems based on a liquid crystal filter or a filter wheel were constructed to facilitate the acquisition of the spectral images and to perform the enhancement operations. A thorough characterisation of the imaging systems determined their limitations and sources of artefacts which could lead to complications in interpreting the enhanced images. The spectral imaging procedure used to visualise blood was incorporated into a near-real-time, hand-held imaging system for the location of blood staining. This prototype imaging system is capable of acquiring two spectral images simultaneously, perform the enhancement procedure, and display the enhanced image within 5 s, which would make it suitable as a non-chemical presumptive screening test for blood at crime scenes.

This study investigated the use of UV-visible spectral imaging for the location and enhancement of substances of forensic interest using targeted approaches based on the spectrum of the substance. Spectral enhancement procedures were developed for blood with and without chemical enhancement, and for latent fingermarks after chemical enhancement. Focus was on substances whose spectrum exhibited a steep change in absorbance or fluorescence over a small wavelength range. Substances with such spectral features were able to be enhanced using arithmetic combinations of two or three spectral images taken at wavelengths near the steep spectral feature. Some enhancement reagents do not react to produce a product with a steep spectral feature suitable for photographic enhancement. In such cases reagents that compliment spectral imaging can be developed. A tridentate ligand for iron(II), BBIDMAPP, which forms a complex with a narrow intense charge-transfer band, was synthesised and was used to visualise muddy shoemarks. UV-visible spectral imaging systems based on a liquid crystal filter or a filter wheel were constructed to facilitate the acquisition of the spectral images and to perform the enhancement operations. A thorough characterisation of the imaging systems determined their limitations and sources of artefacts which could lead to complications in interpreting the enhanced images. The spectral imaging procedure used to visualise blood was incorporated into a near-real-time, hand-held imaging system for the location of blood staining. This prototype imaging system is capable of acquiring two spectral images simultaneously, perform the enhancement procedure, and display the enhanced image within 5 s, which would make it suitable as a non-chemical presumptive screening test for blood at crime scenes.

This study investigated the use of UV-visible spectral imaging for the location and enhancement of substances of forensic interest using targeted approaches based on the spectrum of the substance. Spectral enhancement procedures were developed for blood with and without chemical enhancement, and for latent fingermarks after chemical enhancement. Focus was on substances whose spectrum exhibited a steep change in absorbance or fluorescence over a small wavelength range. Substances with such spectral features were able to be enhanced using arithmetic combinations of two or three spectral images taken at wavelengths near the steep spectral feature. Some enhancement reagents do not react to produce a product with a steep spectral feature suitable for photographic enhancement. In such cases reagents that compliment spectral imaging can be developed. A tridentate ligand for iron(II), BBIDMAPP, which forms a complex with a narrow intense charge-transfer band, was synthesised and was used to visualise muddy shoemarks. UV-visible spectral imaging systems based on a liquid crystal filter or a filter wheel were constructed to facilitate the acquisition of the spectral images and to perform the enhancement operations. A thorough characterisation of the imaging systems determined their limitations and sources of artefacts which could lead to complications in interpreting the enhanced images. The spectral imaging procedure used to visualise blood was incorporated into a near-real-time, hand-held imaging system for the location of blood staining. This prototype imaging system is capable of acquiring two spectral images simultaneously, perform the enhancement procedure, and display the enhanced image within 5 s, which would make it suitable as a non-chemical presumptive screening test for blood at crime scenes.

This study investigated the use of UV-visible spectral imaging for the location and enhancement of substances of forensic interest using targeted approaches based on the spectrum of the substance. Spectral enhancement procedures were developed for blood with and without chemical enhancement, and for latent fingermarks after chemical enhancement. Focus was on substances whose spectrum exhibited a steep change in absorbance or fluorescence over a small wavelength range. Substances with such spectral features were able to be enhanced using arithmetic combinations of two or three spectral images taken at wavelengths near the steep spectral feature. Some enhancement reagents do not react to produce a product with a steep spectral feature suitable for photographic enhancement. In such cases reagents that compliment spectral imaging can be developed. A tridentate ligand for iron(II), BBIDMAPP, which forms a complex with a narrow intense charge-transfer band, was synthesised and was used to visualise muddy shoemarks. UV-visible spectral imaging systems based on a liquid crystal filter or a filter wheel were constructed to facilitate the acquisition of the spectral images and to perform the enhancement operations. A thorough characterisation of the imaging systems determined their limitations and sources of artefacts which could lead to complications in interpreting the enhanced images. The spectral imaging procedure used to visualise blood was incorporated into a near-real-time, hand-held imaging system for the location of blood staining. This prototype imaging system is capable of acquiring two spectral images simultaneously, perform the enhancement procedure, and display the enhanced image within 5 s, which would make it suitable as a non-chemical presumptive screening test for blood at crime scenes.

The scientific study of fingerprints/fingermarks—dactyloscopy—is one of the most important fields in forensic science today. Fingermarks are amongst the most common type of evidence recovered from crime scenes and are arguably the most valued due to the fact that they are, unlike deoxyribonucleic acid (DNA), completely unique to an individual. Fingermarks recovery techniques are constantly evolving and new reagents are always being sought. This project aims to develop and access new fingermark enhancement procedures. The efficacy of an ethanoic solution of phosphomolybdic acid, has been investigated as a latent fingermark enhancement reagent, primarily on porous substrates. After treating samples and exposing them to ultraviolet radiation, the phosphomolybdic acid solution was shown to develop fingermarks to a high quality. Unlike the common amino acid reagents used for the enhancement of fingermarks on porous substrates, ninhydrin and 1,8-diazafluoren-9-one, phosphomolybdic acid stains a range of other compounds found within fingermark deposits, including lipids. The lysochrome diazo dye Oil Red O was used for comparative purposes due to its application in staining some of the same components of fingermark residues that phosphomolybdic acid would be proposed for. Initial results indicate that phosphomolybdic acid is comparable to Oil Red O at developing fingermarks on porous surfaces and may also have applications on non-porous surfaces. A systematic evaluation of solvent carriers was conducted, and whilst many solvents were insufficient, others did show some potential. Primary alcohols such as ethanol, methanol and propan-1-ol all developed fingermarks with identifiable ridge detail. Attempts to mix phosphomolybdic acid with other reagents which react with different fingermark constituents than those phosphomolybdic acid targets were, for the most part unsuccessful. However, not entirely ruled out. Many substrates were tested to observe which developed fingermarks when treated with the phosphomolybdic acid solution. Whilst marks were detected on numerous substrates, paper proved to be the most receptive. Similar stains to the phosphomolybdic acid were tested under the same conditions, however, none were as effective as the phosphomolybdic acid. A non-destructive, non-invasive technique was developed, utilising cuprous metals and their reactions with rubeanic acid. By bringing substrates with fingermarks deposited upon their surface into contact with a copper or copper alloyed plate, it was possible to transfer the fingermark residues to the plate. Forensic gelatin lifters could then be used to lift the marks from the metal plates, these lifted marks could subsequently be treated with a rubeanic acid solution to visualise the fingermarks. The rubeanic acid reacted with the Cu(II) which had been transferred to the fingermark residues to produce a dark product in the pattern of fingermark ridges. The technique was successful at developing fingerprints on semi-porous substrates. The technique was as effective on non-porous substrates, such as glass, but an investigation into the process on porous surfaces was less positive. Attempts to reuse the cuprous metals for the transference of fingermarks after an initial lift resulted in double or ghosted marks being developed, after a thorough wash with soap and water. This was overcome by cleaning with the metal cleaner Brasso. Copper cleaned with Brasso was reused 5 times to show its effectiveness, and adverse effects were minimal. The UK s recent move to polymer banknotes has seen some of the currently used fingermark enhancement techniques for currency potentially become redundant, due to the substrate characteristics of the polymer surfaces. Possessing a non-porous surface with some semi-porous properties, alternate processes are required for polymer banknotes. A preliminary investigation was conducted in to the recovery of fingermarks from polymer notes via vacuum metal deposition using elemental copper. The study successfully demonstrated that fresh latent fingermarks, from an individual donor, could be clearly developed and imaged in the near infrared. By varying the deposition thickness of the copper, the contrast between the fingermark minutiae and the substrate could be readily optimised. Where the deposition thickness was thin enough to be visually indistinguishable, forensic gelatin lifters could be used to lift the fingermarks. These lifts could then be treated with rubeanic acid to produce a visually distinguishable mark. The technique has shown enough promise that it could be effectively utilised on other semi- and non-porous substrates. A follow up group study was less effective than the aforementioned initial study. Many samples were processed using the vacuum metal deposition; incorporating a comparison study between copper and the gold/zinc standard and a depletion trial. However, when imaging was attempted a week after treatment, the results experienced before were unable to be replicated. Attempts to recover samples of radioactive nickel isotope from metal substrates using forensic gel lifters were initially unexceptional. Wipe tests were more successful at recovering the isotope. Experimentation using some non-metallic substrates was more fruitful, the gel lifters were able to recover the radioisotope more readily. Autoradiography showed that, although a weak beta emitter, nickel could be imaged when in sufficient quantities. By using nickel and a short half-life isotope of phosphorus in conjunction with patterned stamps and patterned deposits it was possible to image these patterns by autoradiography of the gels used to lift from the substrates these were deposited upon. These autoradiography images showed enough detail to warrant attempts with a synthetic finger, however, the imaging was insufficient to image the fine details of the friction ridges. Fingermarks deposited on the surface of agar gels showed bacterial growth after incubation for 24 hours. Aseptic transfer of bacterial colonies to fresh agar plates in a typical streak pattern were fruitful. Further transference to a nutrient broth were effective, however, attempts to seed bacterial agar plates for use in inhibition tests were unsuccessful. Overall, phosphomolybdic acid proved to be relatively effective, being able to develop fingermarks on a number of substrates. The copper transfer method, although, less fruitful than PMA showed promise. This lead to the idea of gel lifting from copper VMD treated polymer banknotes which was much more effective. Although, the radioactive and biological techniques showed promise, they were unfortunately unsuccessful at developing fingermarks. A number of the techniques evaluated and developed were successful enough to be published in forensic journals.

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