Examination of heterogeneous crossing sequences between toner and rollerball pen strokes by digital microscopy and 3-D laser profilometry

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.     

无交叉笔画状态下激光打印文字与中性笔书写文字形成时序的实验研究

目的探索无交叉笔画状态下激光打印文字与中性笔书写文字的时序特征及变化规律,以求运用于案件检验。方法以两种不同时序,请5名志愿者分别执不同中性笔在120张A4纸张上书写文字,并使用4台不同型号激光打印机打印文字,再运用奥博视频层晰显微镜对实验样本进行放大观察。结果证实在两种时序条件下制作的实验样本之间存在诸多差异性特征。结论这些差异性特征为准确判定无交叉笔画状态下激光打印文字与中性笔书写文字的时序提供了基础实验依据。     

Determination of the Chronological Order of a Laser Printing and Gel Pen Writing Without any Crossing Strokes

Laser printers and writing instruments are being exploited by the forgers to produce fabricated documents. They often produce such documents by appending genuine signature on a blank sheet and later printing on it. Often these fabricated documents do not contain intersection of strokes and may pose a difficulty to forensic document examiners in analyzing cases related to such documents. Keeping in mind the limited research work done on nonintersecting strokes, the present study has been conducted with an aim to determine the sequence of nonintersecting strokes of gel pens and laser printers. Three hundred samples of nonintersecting strokes of gel pen ink and laser printing were prepared. Of these 300, 150 had laser-printed text below the gel pen strokes and the remaining 150 were prepared with gel pen stokes below the laser-printed text. The samples have been analyzed using Nikon SMZ 800N stereomicroscope. Three micro-conformation features, that is, pattern of toner distribution, ink distribution, and fiber distribution have been observed in the samples. The results demonstrate the successful establishment of sequence of nonintersecting strokes in case of gel pen and laser-printed documents by the determination of micro-conformation features.     

An Examination of the Sequence of Intersecting Seal and Laser Printing Toner Line

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.     

Application of Video Spectral Comparator (absorption spectra) for establishing the chronological order of intersecting printed strokes and writing pen strokes

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.     

Preliminary Study on Determining the Sequence of Intersecting Lines by Fluorescence Technique

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.     

Sequencing the intersections of printed strokes with writing instrument strokes using DocuCentre expert (PIA 6000-EDF)

Introduction of the digital techniques in document examination has encouraged the Forensic Document Examiners to work with better accuracy in non-destructive ways. In this study, the examination of sequence of intersecting strokes of printers (inkjet printer, laser printer, dot-matrix printer) and typewriters with writing instruments (gel ink pen, ballpoint pen and fountain pen) of different colors was carried out by using Docucenter Expert via PIA-6000 software utilizing extended depth of focus. The continuity of the stroke is the only characteristic which has been observed at the point of intersection.     

Determining the sequence of intersecting gel pen and laser printed strokes — A comparative study

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.     

An examination of the sequence of intersecting lines using attenuated total reflectance-Fourier transform infrared spectral imaging

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.     

Application of Raman spectroscopy in forensic investigation of questioned documents involving stamp inks

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).     

Recent developments in writing sequence determination

Two modifications of the Igoe-Reynolds lift technique for examination of line margins to determine the sequence of intersecting ball-point pen strokes are proposed. One for handwriting-typewriting intersections and the other extending the lift technique to ball-point pen writings of some age that are otherwise insensitive to the lift efforts.Attention is also directed to the increased usefulness of spectular light reflection examination resulting from changes in writing materials and instruments, particularly as applied to handwriting-typewriting sequence determination. An inexpensive, readily improvised vertical illuminator is described suitable for use with stereomicroscopes and cameras.     

DVI-300微痕迹色差分析系统对激光打印文字与印章印文交叉时序检验的方法研究

目的研究常见的打印字迹与不同印章印文交叉时序的相关性,为检验提供依据。方法应用DVI-300微痕迹色差分析系统对制成的实验样本进行实体观察,并对微痕迹色差模型图进行特征分析。结果先墨后朱,交叉部位字迹边缘状态完整,等高线宽度、流向未见明显变化;先朱后墨,交叉部位中心字迹等高线排列出现游离状态,色料分布发生数字图形曲面变化。结论用本系统可以观察、分析朱墨交叉部位的微观特征和无损检验研究。     

A lifting process for determining the writing sequence of two intersecting ball-point pen strokes

The authors describe a technique for determining the order in which two intersecting ball-point pen strokes were made by means of lifting part of the ink with KromeKote paper. The KromeKote paper is applied to the intersection with the glossy side against the writing. The back of the lifting paper is rubbed with a blunt pointed instrument using moderate pressure. Study of the lift under low magnification discloses a pattern of edge markings with those from the last written line dominating the intersection. Results show a high percentage of accuracy.     

TOF‐SIMS Analysis of Red Color Inks of Writing and Printing Tools on Questioned Documents

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.     

Determination of writing sequence of strokes of ball-point pen versus ball-point pen and other conventional writing instruments

A simple lifting technique has been suggested to determine the sequence of ball-point pen strokes vis-a-vis the ball-point pen strokes/lead pencils/coloured pencils/fountain pen strokes. The strips of developed photography glossy paper with a white background that are usually thrown away as scraps are used for lifting purpose. The glossy side of the paper is first treated with minimal quantity of pyridine and then placed over the intersection. The back of the lifting paper is rubbed smoothly and uniformly using moderate pressure. The sequence of strokes could be easily determined from the “lift” even by naked eye.     

Determining Line-Crossing Sequences Between Laser Printing and Writing Pen Using Coaxial Light

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.     

Significance of sequence of strokes in Chinese handwriting examination

This paper reports a statistical study on the sequence of strokes of 61 commonly encountered Chinese radicals and characters written by 372 invited subjects. The distribution of different writing sequence of these Chinese radicals and characters was examined. Comparison of the sequence of strokes executed by the subjects with the standard rule of writing these Chinese radicals and characters revealed that around 60% of the subjects wrote in the correct sequence. Pair comparison of sequences of strokes in Chinese handwriting among the 372 subjects was also performed. The results demonstrated that no two individuals wrote all the 61 radicals and characters with the same sequence of strokes. The findings indicate that, despite some basic rules governing the writing sequence of Chinese characters, writers tend to develop their own habits. The findings also support the hypothesis that the handwriting of experienced writers is individual.     

三维立体显微镜在文件检验中的应用

目的通过应用先进的仪器设备,让我们从另一个角度观察文检痕迹特征,寻找到一个文件检验的新视角。方法利用三维立体显微镜,从微观的三维状态下分析文检的痕迹特征(上下位置)。结果能有效区别笔迹书写与印章的先后顺序;打印字迹和印章的先后顺序,同一支笔书写形成的交叉笔划的先后顺序;准确区别打印文书和复印文书等。结论借助三维立体显微镜,能使文件检验水平向前迈进一步。     

Erasable ink; something old, something new

Writing made with the Frixion ® rollerball pen by Pilot ® can be made colourless using the eraser incorporated in each pen. The heat generated by the friction between eraser and paper decolourises the ink and other sources of heat have a similar effect. The original colour of the ink is restored by cooling it to a temperature below 20 °C.