测量笔画增宽度判断激光打印文件朱墨时序初探

目的考察印章印文与激光打印字迹交叉部位的笔画增宽现象,得到朱墨时序判断依据。方法制作两种朱墨时序的实验样本,在VSC-6000文检仪下观察,读数显微镜在相同放大倍率测量,记录增宽度,比较同种品牌印文色料在两种时序下笔画的增宽度。结果相同保存条件下同种品牌印文色料不同时序盖印的实验样本都有增宽现象,先墨后朱时序下增宽度较大。结论该方法可以作为朱墨时序判断依据。     

利用IDMH-Z780系统对碳素钢笔水书写字迹与印章印文交叉时序的无损检验研究

目的研究常见的碳素钢笔水书写笔迹与不同印章印文交叉时序的相关性。方法利用IDMH-Z780系统对制成的实验样本进行微观观察,并对三维数学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,书写笔迹色料分布发生数字图形曲面变化。结论用IDMH-Z780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。     

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。     

正确把握朱墨时序鉴定的几个基本环节

在文书检验中,朱墨交叉顺序的判定一直是一个常见、重要的内容,对于鉴别文书的真伪具有决定性的重要意义。近年来,在科研和检案实践中发现,正确区分印章印文与书写文字的先后顺序,应掌握以下几个基本环节:有统一的技术规范作指导;检验设备应当满足技术规范要求;对字迹和印文色料与纸张结合方式进行检验;检验方法不能单一,应用多种方法相互对照应证;客观评价阳性反应的出现率和排除假阳性反应的干扰。     

荧光检验法在朱墨时序鉴定中的应用研究

朱墨时序鉴定一直是文书司法鉴定实践中常见的鉴定项目,也是研究的热点和疑难问题.通过实验研究并结合检案实践,较系统地阐述了视频荧光光谱检验法和显微荧光检验法在朱墨时序鉴定的具体应用,探讨了荧光检验的技术要点.研究表明,荧光检验法（特别是显微荧光检验法）具有普通显微检验法的优点,同时对普通显微检验法中难以观察到的印文或文字色料荧光特性及色料的微观分布状态,具有明显的检验效果,是普通显微检验法有效的补充检验手段.     

荧光法判断激光打印文件朱墨时序的研究

目的 建立荧光法判断激光打印文件朱墨时序的检验方法,并分析不同型号的激光打印机制成的文件与不同材质的印章印文的采墨时序的特征.方法 利用VSCS000文检仪和Photoshop软件,采用荧光法对激光打印文件与印章印文交叉部位的特征进行检验,并对不同型号的打印机制成文字与不同材质的印章印文交叉部位的荧光特征进行分析比对.结果 发现常出现的共性特征为:制成文字先墨后朱,交叉部位的黑色墨迹颜色变淡并可见紫色荧光;先末后墨,交叉部位常常出现黑色墨迹缺损的现象,在缺损处可见紫色荧光点.但也表现出其特有的特征.结论 不同型号的打印机制成的文件与不同材质的印章朱墨时序所表现出来的特征不尽相同,在具体案件鉴定中应进行综合判断.     

打印复印文件朱墨时序表观特征初探

本文详细介绍了一案例的检验过程,并通过简单实验对激光打印、静电复印形成文件的朱墨时序的表观特征进行了粗浅的探究。总体而言,两种时序在朱墨交叉点的表观特征上具有文字与印文均完整、肉眼感觉文字均压在印文之上的共同点;在两者本质的差异点上,先朱后墨表现为交叉点的墨粉与未交叉部位一致,先墨后朱表现为交叉点的墨粉光泽度增加、具有潮湿感、以及易出现水珠状的印油积聚现象。     

印泥印文人为老化的研究

将不同种类印泥形成的印文试样分别用紫外线灯和烘箱在不同条件下进行人为老化试验,并与自然条件下的印泥印文样本比较,考查了人为老化前后印泥色料在纸张上的聚集状态、荧光、溶解能力、化学成分、灰度等变化规律,从而为此类涉及印泥印文人为老化文件的检验提供依据。     

液相色谱法判断印文形成方式初探

先将真实印文用扫描仪扫描后输入计算机,经过图像处理后用彩色打印机打印,从而伪造印章印文是近年来出现的一种新的、仿真程度较高的伪造印章印文方式.司法鉴定实践表明,这类伪造印文趋于专业化、技术化,且伪造的印文与真实印文相似度较高,依据传统的鉴定依据和方法难以鉴别真伪,甚至可能误导鉴定人员的判断.因此,本文指出,用色谱法对盖印印文和打印伪造印文的成分检测分析,从二者的溶剂和色料成分差异来判断其真实的形成方式,为科学的检验鉴定工作提供借鉴和依据.     

印文鉴定相关问题探讨——高仿真印文鉴定

当前,与印文鉴定相关的并在鉴定实践中经常遇到的新问题和难点问题有高仿真印文的鉴定、变造印章问题、利用真实印文变造文件、同版印章印文、朱墨时序等,本文就高仿真印文的鉴定进行了系统阐述,介绍了各种高仿真印文,包括各种高仿真印章的盖印印文、复制印文、转印印文的伪造手段及其特点,并提出了高仿真印文的鉴定思路和要点。     

An examination of handwritten signatures forged using photosensitive signature stamp

Signature examination is the most common examination performed by any document examiner. Determination of the authenticity of a handwritten signature on a questioned document is an important task for forensic document examiners in the forensic science field. As a result of continuous developments in technology, a signature stamp can now be created using a photosensitive seal to enable the reproduction of a handwritten signature. These stamps are commonly used in China and several other countries. In this study, 10 types of black photosensitive stamp-pad ink, 10 brands of fountain pen ink, 15 types of black gel ink and six types of black erasable gel ink found on the Chinese domestic market were collected and 10 photosensitive signature stamps were created using the signatures of 10 people. Microscopic analysis, infrared (IR) and fluorescence analyses and microspectrophotometry (MSP) techniques were used to examine the resulting photosensitive signature stamp impressions when applied to printing papers, writing papers and invoice papers. By comparing the printing and spectral characteristics of the photosensitive signature stamp impressions with those of the signatures executed using the fountain pens, gel pens and erasable gel pens, it was possible to determine whether each signature was written or stamped using a photosensitive signature stamp. To validate these results, a 96.7% absolute accuracy and a 99.3% detection rate were achieved over a total of 150 blind tests conducted by five forensic document examiners, thus demonstrating that a combination of the four analysis methods used in this work can provide a more scientific approach and improve the accuracy and the detection rate of the examination process.

KEY POINTS

• A signature stamp is a photosensitive seal made in the style of a handwritten signature.
• Although microscopic analysis can usually provide better examination results, a comprehensive examination method that includes microscopic analysis and ink composition analysis is required to improve the accuracy and the detection rate of the examination process.
• This study collected and tested photosensitive stamp-pad inks, fountain pen inks, gel inks and erasable inks.
• Infrared and fluorescence analyses and microspectrophotometry were able to distinguish the photosensitive ink from both erasable ink and fountain pen ink.

Supplemental data for this article are available online at https://doi.org/10.1080/20961790.2021.1898755.     

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.     

Differentiation between inks of the same brand by infrared luminescence photography of their thin-layer chromatograms

A case is reported involving a U.S. Treasury check with an altered amount payable. The ink in the alteration and the ink in the endorsement signature were compared with ink from three Skilcraft ball pens all having Skilcraft black ink ball pen refills. Infrared luminescence photography of their thin-layer chromatograms revealed differences between the inks in the three pens.     

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.     

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.     

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).     

Application of Micro‐Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy to Ink Examination in Signatures Written with Ballpoint Pen on Questioned Documents

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.     

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.