显微激光拉曼光谱技术区分喷墨打印墨迹研究

目的运用激光显微共聚焦拉曼光谱仪对打印墨水的墨迹样品进行检验。方法采用514nm激发波长,测得EPSON、HP、CANON等3个品牌21种型号墨迹样品的拉曼光谱。结果根据拉曼峰位的异同,可将21种型号墨迹样品分为8大类。结论该方法可以快速区分常见不同种类打印墨水墨迹,为印刷文件的检验鉴定提供方法参考。     

印文墨迹分布特征及材料特性在盖印时间鉴定中的应用

通常情况下一份完整的文件有抬头、内容、落款签名或印文、落款时间等多个要素组成,文件是否真实有效,取决于与该文件有关的诸多要素。在许多案件的审理过程中,文件形成的确切时间往往是当事各方主要争议的焦点,特别是文件上印章印文的盖印时间更是最为常见的提请鉴定的问题。根据鉴定实践和实验研究,对印文墨迹分布特征及材料特性在印章印文盖印时间鉴定中的应用,及在鉴定过程中应当引起注意的相关事项进行探讨,并通过实际案例予以说明。     

文件上有色指印非纹线特征的应用研究

为了充分地发掘模糊指印形态特征在司法实践中的可用性和实用性,我们利用文件上有色指印的阶段性痕迹--墨迹边缘状态、积墨形态分布“、空白”形态分布及其相互位置关系等非纹线特征,分析研究了不同捺印人以油墨为介质连续捺印的样本指印50组共200枚,结果发现使用非纹线特征能够准确地分辨出同一手指连续捺印的同组指印。本文还对应用指印非纹线特征的各项技术要点进行了讨论,并且列举了该方法用于鉴定实践的三个成功案例。指印非纹线特征的应用不仅改变了对模糊指印只能出“具不具备鉴定条件”的结论模式,而且使适合使用该方法的被检指印形成相对时间的难题得到解决。     

通过辨别、对比和检验材料中的变化测定文件日期

对一份文件最早制成时间的检验一直以来都是全世界文检界的难题之一。核实可疑文件的制成时间没有统一的方法,目前主要通过对纸张、墨迹、打字机、复印机、打印机、传真机、印刷品,以及笔迹和签名等因素的检验来确定一份文件的制成时间。文件检验人员需要充分利用他们手中的文件的内容及文件周边信息所反映出来的条件和材料,进而得出结论。     

通过辨别、对比和检验材料中的变化测定文件日期

对一份文件最早制成时间的检验一直以来都是全世界文检界的难题之一。核实可疑文件的制成时间没有统一的方法,目前主要通过对纸张、墨迹、打字机、复印机、打印机、传真机、印刷品,以及笔迹和签名等因素的检验来确定一份文件的制成时间。文件检验人员需要充分利用他们手中的文件的内容及文件周边信息所反映出来的条件和材料,进而得出结论。     

浅谈计算机技术在文检鉴定中的应用

当今是信息时代，计算机技术已在各个领域广泛运用，但该项技术在司法鉴定领域的运用还有待于探索、开发。为此，笔者拟从笔迹鉴定，印章鉴定、污损文件鉴定、印刷文件鉴定四个方面对计算机技术在文件检验鉴定中的应用进行探讨。     

文件形成时间鉴定的统计学方法初探

文件形成时间的鉴定问题一直是文书鉴定领域最具争议和挑战的疑难问题．尤其是如何利用文件要素与时间的关系,定量分析判断文件的形成时间。通过对一起印章印文盖印时间鉴定的实际案例,探讨了如何运用统计学方法定量分析印章印文阶段性特征中的定量特征与印文盖印时间之间关系,为印章印文盖印时鉴定提供一种定量分析的方法,也为如何进一步运用统计学方法定量分析文件形成时间的类似问题提供了一种研究思路。     

一起欠款纠纷案中添加变造文件的检验

添加变造文件的检验鉴定具有一定的难度。本文通过对一起欠款纠纷案的案情分析，用系统思维的方法，具体采用荧光检验法对案件进行鉴定，从而总结出对添加变造文件这一类案件的检验思路和方法。     

笔迹鉴定认定案件中的误检

文检工作的最重要的一项就是笔迹鉴定，一般约占文检总量的60％～70％。因笔迹鉴定是一门主客观相结合的科学，相对于伪造变造文件、文件形成时间、文书材料鉴定而言，其主观性要大一些，故常有笔迹鉴定结论不一致的现象。其中，肯定有些是误检．何种原因所致，如何尽可能的降低误检率，是笔迹鉴定应解决的长期课题，     

电子文件的法律效力探析

电子文件随着计算机技术和网络技术的发展而迅速增长。本文围绕其法律效力的有关问题进行了初步探讨，提出确认电子文件法律效力的前提是确保其原始性，形成电子文件法律效力的条件是其具有证据能力和证明力，并且从认识、管理、技术和法律四个方面指出了实现电子文件法律效力的障碍和保证其法律效力的措施。     

墨水书写时间测定的进展

本文追述了从20世纪20年代初到90年代末书写墨水的时间测定的进展.这包括,介绍新检验方法建立所需遵循的基本要求;推荐目前案件检验的工作程序,即墨水种类的确定,可疑文件的外观检验,同牌号、同配方、同批号比对样本的寻找;评述目前已为办案使用的各种书写年代测定的方法,如扩散法,转印法,染料比值法,气相色谱法、溶剂萃取法,差示扫描量热法等;以及讨论了有望用于年代测定的一些新技术,如用于钢笔墨水的电化学法,光谱法和用于圆珠笔墨水的显微分光光度法,付里叶变换拉曼光谱法等.     

Preliminary Studies on the Absorbance Ratio Method Used to Determining the Age of Stamp‐pad Ink Seal

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.     

The identification of 2-phenoxyethanol in ballpoint inks using gas chromatography/mass spectrometry--relevance to ink dating

Developing and implementing a generally accepted procedure for the dating of ink found on documents using dynamic approaches has been a very formidable undertaking by forensic document examiners. 2-Phenoxyethanol (PE), a common volatile organic compound found in ballpoint inks, has been recognized for over a decade as a solvent that evaporates as ink ages. More recently, investigations have focused on the solvent loss ratio of PE prior to and after heating. To determine how often PE occurs in ink formulations, the authors analyzed 633 ballpoint inks utilizing a gas chromatograph/mass spectrometer. 2-Phenoxyethanol was identified in 85% (237/279) and 83% (293/354) of black and blue inks, respectively.     

Application of the micro-FTIR spectroscopy, Raman spectroscopy and XRF method examination of inks

In routine examination of inks on questioned documents non-destructive analytical methods, such as microscopic and optical techniques are applied first. However, they are often insufficient to identify the inks used for the preparation of the document. In such cases, it is necessary to apply chemical methods that normally cause partial destruction of the examined material. The aim of this work was to evaluate the possibility of discrimination between inks by the use of spectrometric methods, i.e. micro-FTIR spectroscopy, Raman spectroscopy and XRF. About 70 samples of blue and black ballpoint pen and gel inks were examined. It was found that about 90% of the samples of the same type and colour could be distinguished using these methods.     

How Much Can a Forensic Laboratory Do to Discriminate Questioned Ink Entries?

Questioned document examiners are frequently required to determine whether the questioned ink entries on a document are written with the same ink, either for forged document identification or relative ink dating. How many methods are sufficient to discriminate potentially different inks? In this paper, 18 blue ballpoint inks were first nondestructively examined with a video spectral comparator. The ink entries were subsequently extracted with organic solvents for analysis of the volatile solvents and dyes by GC/MS, TLC, and LC‐MS/MS. The 18 ink samples were divided into 10, 9, 12, and 14 categories by these four methods, respectively. With the combined results, there were only two inks that remained indistinguishable, but they were further differentiated by microscopy. Therefore, to achieve effective discrimination of ballpoint ink entries, the authors suggest that a complete examination should include an analysis of their optical features, volatile solvents, and dyes as well as the ink quality.     

Changes in composition of ballpoint pen inks on aging in darkness

A method for comparison of the relative age of ink entries written by the same ballpoint pen on documents stored in darkness is presented. Inks were extracted from the document and analyzed by HPLC (high performance liquid chromatography). On aging, changes in the chemical composition of the inks were noted. These changes were similar to those observed when inks were exposed to light or heat. The aging was followed by using ternary diagrams constructed for dyes generally present in blue-colored inks--Crystal Violet, Methyl Violet, and Tetramethyl Para Rosaniline. The procedure is applicable for relative dating of ink entries in diaries, notebooks, etc., where often several ink entries are written by the same ink. However, a prolonged exposure of the document to daylight and/or artificial light (light from fluorescent tubes) as well as to extensive heat will render the whole procedure inapplicable. An example of the use of the proposed method in casework is given.     

Minimum requirements for application of ink dating methods based on solvent analysis in casework

Several ink dating methods based on solvents analysis using gas chromatography/mass spectrometry (GC/MS) were proposed in the last decades. These methods follow the drying of solvents from ballpoint pen inks on paper and seem very promising. However, several questions arose over the last few years among questioned documents examiners regarding the transparency and reproducibility of the proposed techniques. These questions should be carefully studied for accurate and ethical application of this methodology in casework. Inspired by a real investigation involving ink dating, the present paper discusses this particular issue throughout four main topics: aging processes, dating methods, validation procedures and data interpretation. This work presents a wide picture of the ink dating field, warns about potential shortcomings and also proposes some solutions to avoid reporting errors in court.     

Dating of Inkpad Seals Using the Extraction Rate Method: Preliminary Findings

Inkpad seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, three different brands of inkpads and four different types of paper were used to make diachronic samples of the seals. A double‐solvent extraction method was employed to date the inkpad seals by comparing extraction rates with inks of known age. Cyclohexane was selected as a weak solvent, and chlorobenzene was selected as a strong solvent. After testing, curves were created to show the relationship between the extraction percentage of ink and the date of the seals. The experimental results showed that the extraction rate method was applicable for the relative dating of inkpad seals in some cases where the seal was placed on the document within 6 months.     

双溶剂提取法判定印泥印文形成时间的初探

目的通过双溶剂提取法判定印泥印文的形成时间,为判定文件的真伪提供重要依据。方法选用6种不同品牌的印泥和4种纸张分别制作印泥印文的历时性样本,通过实验确定适用于双溶剂提取法判定印泥印文形成时间的弱提取剂和强提取剂;确定薄层扫描时狭缝的大小和扫描波长;绘制盖印时间与提取率的关系曲线。结果弱提取剂为50％的甲酸溶液,强提取剂为N,N-二甲基甲酰胺,狭缝大小为12．00mm×0．60mm,扫描波长为485nm,得到了盖印印文形成后半年内印泥提取率随印文形成时间变化的关系曲线。结论双溶剂提取法是判定印泥印文形成时间的一种有效方法。     

A logical framework to ballpoint ink dating interpretation

Since its beginnings, the forensic field of questioned documents has been concerned with the dating of inks. Ink ageing processes follow complex paths. Disagreements about the feasibility of current methods have been voiced worldwide among the scientific and legal communities. This controversy has been the starting point of the present work. Its aim was that of evaluating the interpretation processes of such evidence. Subjective statistical data have been assigned from earlier works and illustrate the kind of data necessary to date ballpoint ink, and how to use it for this purpose. This work also suggests that the court and scientific requirements for standards of reliability are not yet fulfilled by actual ink dating methods for regulatory use in expert testimony.