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1.
Fluorescence microscope is considered to be one of the most effective ways to examine the sequence of intersecting seal and toner lines of questioned documents. In reality, however, the toner (mainly divided into compact and noncompact toners) and seal of a questioned document have such a complex morphology and sequence of crossing lines that current methods cannot meet the requirement of practical document identification. In view of the challenges of document examination, a laser fluorescence microscope and method are developed in this study. The developed microscope provides additional functionality to traditional fluorescence microscopes of transmitted light modality, laser excitation, selectable excitation wavelength, and selectable fluorescence filters. The results obtained from the method of comparisons between transmitted light and fluorescence modalities were positive under most conditions, particularly for noncompact toner examination for which a 100% accuracy rate and 90% detection rate were achieved in blind testing. 相似文献
2.
Examining the sequence of intersecting seal and laser printing line is a significant method of determining the authenticity and validity of documents. In this study, five brands of stamp pad inks, three types of inkpads and seven kinds of laser printers were used to make heterogeneous line intersections. Observation method of physical characteristics, scraping technique and fluorescence method was used to determine the sequence of intersecting lines. Distinguishing features were noted between the materials produced in both sequences. As the results obtained from the study were positive, these features might provide a scientific basis for accurately determining the sequence between laser printing line and inkpad (stamp pad ink) seal. 相似文献
3.
In this study, the potential of attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectral imaging as a technique to determine the sequence of line crossings was examined. The technique was successful in determining the sequence of heterogeneous line intersections produced using ballpoint pens and laser printers. By imaging at characteristic frequencies, it was possible to form spectral images showing the spatial distribution of the materials. By examining the spectral images from the inks, it was possible to determine whether the ink was above or below the toner. In blind testing, ATR-FTIR spectral imaging results were directly compared to those obtained by eight experienced forensic document examiners using methods regularly employed in casework. ATR-FTIR spectral imaging was shown to achieve a 100% success rate in the blind tests, whereas some incorrect sequence determinations were made by the forensic document examiners when using traditional techniques. The technique was unable to image ink-jet printing, gel pens, roller ball pens, and felt-tip pens, and was also unable to determine the sequence of intersecting ballpoint pen lines. 相似文献
4.
The relative chronological sequence of intersecting gel pen ink lines and laser printed marks has been determined using optical methods. The results were obtained by observing spectral reflection, relative sheen, skipping and gaps of gel pen ink strokes at the point of intersection. The intersections are observed under stereomicroscope and digital microscope. The effectiveness of both the optical instruments for sequence of the strokes has been compared. The sequence of intersecting lines (of same colour, different colours and where one of the strokes is darker) has been established. 相似文献
5.
Xiang Wu Ph.D. Guoliang Ouyang M.Sc. Biao Li M.Sc. Lan Cui M.Sc. Guanglei Zhou M.Sc. 《Journal of forensic sciences》2020,65(4):1242-1246
Determining the application sequence of hand-written pen ink and printer toner lines has attracted significant interest in questioned document examination. This study uses coaxial light to determine line-crossing sequences, with intersections observed under a VSC600 forensic document workstation and a Leica M205A Stereo-microscope. Results show that reflected light at intersections and color contrast between intersections and nonintersections was observed when a hand-written ink line passes over a toner line, while a toner line passing over a written line appeared dull, with no color contrast. The procedure was tested under a range of conditions, such as types of writing pens and laser printers, the writer, and writing pressure, with the latter playing an important role in the evaluation. To validate the results, a 90% detection rate and 98% accuracy rate were achieved from 50 samples of blind testing, which is more effective than optical microscopy. 相似文献
6.
The sequence of intersecting strokes of laser printers (black, blue, red and green) and typewriter ink (black) with the strokes of gel pen ink, ballpoint pen ink and fountain pen ink (black, blue, red and green) has been determined by studying their absorption spectra. The absorption spectra have been generated for each of the two pure inks (i.e. A and B) and points of their intersections (i.e. A over B and B over A) by using Video Spectral Comparator (VSC-2000-HR). The study was carried out with an assumption that the peak characteristics of spectra from the point of intersection should correspond to the peak characteristics of pure ink which was executed later. It was observed that the absorption spectrum of intersection corresponds with either the laser printer or the typewriter ink stroke, whether these strokes were executed earlier or later than the writing instrument strokes. As the results obtained from the study were negative, the FDEs are advised against the practice of this technique in the examination of the sequence of intersecting strokes for these specified inks. 相似文献
7.
Biao Li M.Sc. 《Journal of forensic sciences》2016,61(3):809-814
The potential of microspectrophotometry as a technique to determine the sequence of intersecting lines was examined. The technique was used to determine the sequence of heterogeneous line intersections produced using inkpad, stamp‐pad ink and ballpoint pens, gel pens, fountain pens, laser and ink‐jet printers. The study was carried out with an assumption that the peak characteristics of spectra from the point of intersection should correspond to the peak characteristics of pure ink which was executed later. According to spectral reflectance curves, microspectrophotometry was possible to determine whether the ink was above or below the inkpad/stamp‐pad ink seals. In blind testing, microspectrophotometry technique results were directly compared to those obtained by five experienced forensic document examiners using optical microscopy regularly employed in casework. As the results obtained from the study were positive, microspectrophotometry technique was found to be very successful in determining the sequence of heterogeneous line intersections under some conditions. 相似文献
8.
Jihye Lee Ph.D. Yun Sik Nam Ph.D. Jisook Min Ph.D. Kang‐Bong Lee Ph.D. Yeonhee Lee Ph.D. 《Journal of forensic sciences》2016,61(3):815-822
Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) is a well‐established surface technique that provides both elemental and molecular information from several monolayers of a sample surface while also allowing depth profiling or image mapping to be performed. Static TOF‐SIMS with improved performances has expanded the application of TOF‐SIMS to the study of a variety of organic, polymeric, biological, archaeological, and forensic materials. In forensic investigation, the use of a minimal sample for the analysis is preferable. Although the TOF‐SIMS technique is destructive, the probing beams have microsized diameters so that only small portion of the questioned sample is necessary for the analysis, leaving the rest available for other analyses. In this study, TOF‐SIMS and attenuated total reflectance Fourier transform infrared (ATR‐FTIR) were applied to the analysis of several different pen inks, red sealing inks, and printed patterns on paper. The overlapping areas of ballpoint pen writing, red seal stamping, and laser printing in a document were investigated to identify the sequence of recording. The sequence relations for various cases were determined from the TOF‐SIMS mapping image and the depth profile. TOF‐SIMS images were also used to investigate numbers or characters altered with two different red pens. TOF‐SIMS was successfully used to determine the sequence of intersecting lines and the forged numbers on the paper. 相似文献
9.
Chelsea E. Johnson M.S. Paul Martin Ph.D. Katherine A. Roberts Ph.D. Tatiana Trejos Ph.D. Ruthmara Corzo B.S. Jose R. Almirall Ph.D. Alan M. Safer Ph.D. 《Journal of forensic sciences》2018,63(1):66-79
This study applies Raman microspectroscopy to differentiate the chemical components in printing inks of different brands, colors, and type using the 532 nm and 785 nm excitation wavelengths. Spectra were collected from 319 inks (78 inkjet, 76 toner, 79 offset, and 86 intaglio) representing various colors. Comparisons were performed to calculate discrimination capability percentages for each ink type. Overall, Raman microspectroscopy differentiates according to the following hierarchy: intaglio (96%), inkjet (92%), offset (90%), and toner (61%). The ability of Raman microspectroscopy to differentiate between same‐colored inks from different brands was dependent on the color and ink analyzed. Based on ink color, the discrimination capability ranged from 75 to 94% (inkjet), 0 to 86% (toner), and 0 to 77% (offset). Copper phthalocyanine was detected in cyan inks and various intaglio inks, while carbon black was identified in black inkjet, offset, and intaglio inks. 相似文献
10.
Ning Zhang Ph.D. Peng Jiang B.S. Weixin Wang M.S. Chengming Wang Ph.D. Lanchi Xie M.S. Zhigang Li B.S. Wei Huang Ph.D. Gaojun Shi B.S. Lei Wang M.S. Yuwen Yan M.S. Shuhui Gao Ph.D. 《Journal of forensic sciences》2020,65(6):2071-2079
Determining the sequence of intersecting lines is a significant issue in the forensic document examination that can reveal the fraud or distinguish between different allegations. Optical coherence tomography (OCT) is a high-resolution cross-sectional imaging technique that has been introduced into forensic science field recently. The potential of OCT as a novel method to determine the sequence of intersecting lines was examined for the first time. In this study, a spectral-domain OCT system with a center wavelength of 900 nm was employed to perform nondestructive examination on determining the sequence of 18 heterogeneous intersecting line samples produced using three types of gel pens and three brands of stamp pad ink seals. Two-dimensional (2D) cross-sectional, and three-dimensional (3D) volumetric images of the intersecting lines were obtained by the OCT system. Several features were noted and analyzed to successfully determine the sequence of all the 18 samples. Blind tests were also conducted to demonstrate the effectiveness of OCT technique. The results illustrate that OCT technology can provide an effective and accurate method for sequencing intersecting lines of gel pen ink and seal ink, which may complement the conventional methods used in the examination of questioned documents. 相似文献
11.
Yun Sik Nam Ph.D. Jin Sook Park M.S. Yeonhee Lee Ph.D. Kang‐Bong Lee Ph.D. 《Journal of forensic sciences》2014,59(3):800-805
Questioned documents examined in a forensic laboratory sometimes contain signatures written with ballpoint pen inks; these signatures were examined to assess the feasibility of micro‐attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy as a forensic tool. Micro‐ATR FTIR spectra for signatures written with 63 ballpoint pens available commercially in Korea were obtained and used to construct an FTIR spectral database. A library‐searching program was utilized to identify the manufacturer, blend, and model of each black ballpoint pen ink based upon their FTIR peak intensities, positions, and patterns in the spectral database. This FTIR technique was also successfully used in determining the sequence of homogeneous line intersections from the crossing lines of two ballpoint pen signatures. We have demonstrated with a set of sample documents that micro‐ATR FTIR is a viable nondestructive analytical method that can be used to identify the origin of the ballpoint pen ink used to mark signatures. 相似文献
12.
Stamp pad inks from different manufacturers across India have been analyzed to investigate the feasibility of Raman scattering as a tool for forensic analysis of questioned documents involving stamp inks. Nine different stamping inks were analyzed by both Raman spectroscopic and HPTLC methods. The results demonstrate the effectiveness of these methods in classifying the investigated stamping inks based on their spectral pattern and HPTLC chromatogram. Raman scattering tool was able to determine the sequence of heterogeneous intersection strokes involving a blue stamp pad ink and other writing instruments, such as ballpoint pen ink (red and black), pencil and laser printer toner. However, this method was unable to resolve the exact sequencing for the intersection strokes involving investigated stamp ink and blue ballpoint ink or gel pen ink (all colors). 相似文献
13.
Determination of the sequence of intersecting lines using Focused Ion Beam/Scanning Electron Microscope 下载免费PDF全文
Jiye Kim M.Sc. MinJung Kim M.Sc. JinWook An Ph.D. Yunje Kim Ph.D. 《Journal of forensic sciences》2016,61(3):803-808
The aim of this study was to verify that the combination of focused ion beam (FIB) and scanning electron microscope/energy‐dispersive X‐ray (SEM/EDX) could be applied to determine the sequence of line crossings. The samples were transferred into FIB/SEM for FIB milling and an imaging operation. EDX was able to explore the chemical components and the corresponding elemental distribution in the intersection. The technique was successful in determining the sequence of heterogeneous line intersections produced using gel pens and red sealing ink with highest success rate (100% correctness). These observations show that the FIB/SEM was the appropriate instrument for an overall examination of document. 相似文献
14.
Preliminary Study on Determining the Sequence of Intersecting Lines by Fluorescence Technique 下载免费PDF全文
Biao Li M.Sc. Guo liang Ouyang M.Sc. Peng nan Zhao M.Sc. 《Journal of forensic sciences》2018,63(2):577-582
The determination of the sequence of intersecting lines is an important part of questioned document examinations. A fluorescence technique was used to determine the sequence of heterogeneous intersecting lines produced using inkpad ink, stamp‐pad ink, ballpoint pens, gel pens, fountain pens, colorants of carbon paper, photocopiers, laser printers, and inkjet printers. A SteREO Discovery.V20 equipped with the ZEN Blue Lite software was chosen to perform the tests.As the results obtained from the study were positive under most conditions, the fluorescence technique was found to be very successful in determining the sequence of intersecting lines from ballpoint pen, gel pen, fountain pen, photocopier, laser and inkjet printers, and inkpad inks. The method was also successful in determining the sequence of intersecting lines from ballpoint pen, photocopier, laser printer, and stamp‐pad inks under most conditions. The technique was not successful in determining the order of crossing lines blending together. 相似文献
15.
Preliminary Studies on the Absorbance Ratio Method Used to Determining the Age of Stamp‐pad Ink Seal
Guoliang Ouyang M.Sc. Biao Li M.Sc. Pengnan Zhao M.Sc. Xingfei Guo M.Sc. Changliang Wang M.Sc. 《Journal of forensic sciences》2019,64(4):1203-1212
Stamp‐pad ink seals are often placed on important documents, and determining the dating of stamp‐pad ink seal is important to assess the authenticity of a document. In this study, 20 different brands and types of stamp‐pad inks were classified by ultraviolet visible spectrophotometer. Six different brands and types of papers were classified by micro‐Fourier transform infrared spectrometer and visual spectral comparator 6000. Three different brands of stamp‐pad inks and two different types of paper were used to make diachronic samples of the seals. A method was employed to date the stamp‐pad seals by comparing absorbance ratios and inks of known age. Curves were created to show the relationship between the absorbance ratio of ink and the age of the seals. The experimental results showed that the absorbance ratio method was applicable for the relative dating of stamp‐pad ink seals in some cases where the seal was placed on the document within 10 weeks. 相似文献
16.
Evaluation of the Forensic Utility of Scanning Electron Microscopy‐Energy Dispersive Spectroscopy and Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry for Printing Ink Examinations 下载免费PDF全文
Ruthmara Corzo B.Sc. Kiran Subedi Ph.D. Tatiana Trejos Ph.D. José R. Almirall Ph.D. 《Journal of forensic sciences》2016,61(3):725-734
Improvements in printing technology have exacerbated the problem of document counterfeiting, prompting the need for analytical techniques that better characterize inks for forensic analysis and comparisons. In this study, 319 printing inks (toner, inkjet, offset, and Intaglio) were analyzed directly on the paper substrate using scanning electron microscopy‐energy dispersive spectroscopy (SEM‐EDS) and Laser Ablation‐Inductively Coupled Plasma‐Mass Spectrometry (LA‐ICP‐MS). As anticipated, the high sensitivity of LA‐ICP‐MS pairwise comparisons resulted in excellent discrimination (average of ~ 99.6%) between different ink samples from each of the four ink types and almost 100% correct associations between ink samples known to originate from the same source. SEM‐EDS analysis also resulted in very good discrimination for different toner and intaglio inks (>97%) and 100% correct association for samples from the same source. SEM‐EDS provided complementary information to LA‐ICP‐MS for certain ink types but showed limited utility for the discrimination of inkjet and offset inks. 相似文献
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18.
The determination of line crossing sequences between rollerball pens and laser printers presents difficulties that may not be overcome using traditional techniques. This research aimed to study the potential of digital microscopy and 3-D laser profilometry to determine line crossing sequences between a toner and an aqueous ink line. Different paper types, rollerball pens, and writing pressure were tested. Correct opinions of the sequence were given for all case scenarios, using both techniques. When the toner was printed before the ink, a light reflection was observed in all crossing specimens, while this was never observed in the other sequence types. The 3-D laser profilometry, more time-consuming, presented the main advantage of providing quantitative results. The findings confirm the potential of the 3-D laser profilometry and demonstrate the efficiency of digital microscopy as a new technique for determining the sequence of line crossings involving rollerball pen ink and toner. 相似文献
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20.
Kai‐kai Li Ph.D. 《Journal of forensic sciences》2019,64(3):897-906
In document examination, it is of great importance to determine the composition of seal ink with different imprint times, and spectroscopic methods are widely used today. In this research, the diffusion of seal inks from three different brands on the same type of paper is monitored in situ by microinfrared spectroscopy and microinfrared imaging technology. The area of the absorption peak at 1743 cm?1 gradually decreases with increasing diffusion time. The diffusion kinetics of seal ink on paper are also studied by analyzing the infrared spectra of seal inks at the same measuring point with different diffusion times. The research provides a basic study in understanding the diffusion behavior of seal ink on paper over short time spans. 相似文献