文件形成时间检验方法及实践中存在的问题

文件形成时间检验是文件检验领域里比较疑难的检验项目。目前的检验方法从检验思路上大致分为确定文件形成时间上限的方法和确定文字色料随时间变化规律的方法两大类。前者通过对检材及检材记载内容进行分析、调查研究来确定文件形成时间;后者通过物理化学分析的方法,来确定文件形成时间。以上方法在实践中存在一定的局限性,我们还可以用系统论的方法从案情分析、纸张信息、文字特征、理化分析等方面进行综合检验分析, 扩大检验范围。今后我们应当进一步强调文件形成时间检验工作的科学态度,加强科学研究,探索更加有效的检验方法。     

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。     

特殊文件相对形成时间的鉴定

伪造、变造、异常处理文书的书写时间鉴定在诉讼中的作用越来越重要。笔者在多年的文书鉴定工作中曾遇到多起特殊处理的文件,如人为老化文件、塑封文件,污染文件以及书写于传真纸、宣纸等特定材料上的文件,在对这些文件的检验过程中,笔者进行了部分研究,获得一些实际体会。     

文件检验的困惑与反思

文件检验做为一门已经成熟的物证技术,新的研究和经验层出不穷,但多未能突破文件检验的常规方法,新的检验仪器设备不断更新,仍然无法解除文件检验的方法局限.本文通过对同一认定理论的认识,尝试用检验鉴定的基础理论对文件检验中发现的问题进行反思,力图用最原始、最根本、最有效的理论解除文件检验中发现的困惑.     

新形势下如何发挥文件检验鉴定的作用

随着我国经济的迅速发展和法制化建设进程的加快,给文件检验鉴定工作增加了难度,也提出了更高的要求。当前随着社会治安形势日趋复杂,法制建设日趋完善,公安工作对证据的要求越来越高,目前的文件检验鉴定工作已不能完全适应新形势、新任务的要求。     

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。     

公安工作文件检验鉴定的重要作用

实践是法律与制度的本质,实践法律制度不可或缺的方式以及渠道在于执行。目前,由于社会治安逐渐繁杂的情形,法制建设渐渐得到完善,公安工作在证据方面有着更高的需求,现在的文件检验鉴定工作对于新的任务与形势已经不能满足其需求。本文初步的阐述了怎样进行文件检验以及它的重要作用。     

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。     

文件检验中的辩证思考

文件检验作为技术侦查与司法鉴定活动中的一项专门手段,文检工作者不仅要掌握文检学的专业理论知识与检验方法,还要在实际的检验鉴定工作中坚持以唯物辩证法为指导,客观全面地对文件物证进行分析检验.文件物证及其特征是普遍性与特殊性、共性与个性的矛盾关系的统一体.在实际的检验鉴定工作中我们要结合具体案情,进行辩证地选取、分析、比对,使鉴定结论更具科学性,也能更好地体现公平、公正的法律公意和维护当事人的合法利益.     

文件检验技术与书画作品真伪鉴定

文件检验技术是刑事科学技术的重要组成部分，同时也是识别各类文书真伪的重要手段。文件检验学的检验对象是“文件”，就书画作品的表现形式来看，其无疑也被涵盖其中，因此，书画作品是传统书画鉴定的对象，更是文件检验学的对象之一，传统书画鉴定方法与运用文检技术检验书画作品的真伪二者应是互为补充的关系。     

Identification and dating of the fountain pen ink entries on documents by ion-pairing high-performance liquid chromatography

A novel approach for the identification and dating of the fountain pen ink entries on paper has been established by ion-pairing high-performance liquid chromatography (IP-HPLC). Twelve black and six red fountain inks have been collected, and their ink entries have been prepared by drawing lines on paper. The chromatographic conditions for separation of their dye components after extraction with solvents were optimized. Under the optimized conditions, the 18 fountain pen inks were differentiated individually by comparing the number of detectable main or minor dye components, and the relative peak intensities of each component. The ink entries were artificially and naturally aged, and the analysis results showed that the ink dye components were significantly decomposed when exposed to UV or fluorescent light compare to those of inks stored under natural condition. The changes of the relative peak height for the dye components were linearly related to the aging time, especially under natural aging conditions. The degradation characteristics of the dye components under different aging conditions provide scientific evidences for dating of the suspicious fountain pen ink entries on document.     

The probative character of Forensic Handwriting Examiners' identification and elimination opinions on questioned signatures

This 5-year study investigated the character of Forensic Handwriting Examiners' (FHEs) authorship opinions on questioned signatures through the medium of blind validation trials. Twenty-nine thousand eight hundred and eleven authorship opinions were expressed by FHEs on trial kits comprising randomized questioned genuine signatures (written by the specimen writer), disguised signatures (written by the specimen writer) and simulated signatures (not written by the specimen writer). Results showed that, as a group, FHEs were significantly more confident at identifying writers' genuine signatures than identifying writers' disguised signatures or eliminating specimen writers from having authored simulated signatures. It is proposed that the difference in FHE confidence arises from the difficulty they have in deciding which alternative authorship explanation accounts for perceived combinations of similar and dissimilar features between specimen and questioned signatures.     

The probative character of Forensic Handwriting Examiners’ identification and elimination opinions on questioned signatures

This 5-year study investigated the character of Forensic Handwriting Examiners’ (FHEs) authorship opinions on questioned signatures through the medium of blind validation trials. Twenty-nine thousand eight hundred and eleven authorship opinions were expressed by FHEs on trial kits comprising randomized questioned genuine signatures (written by the specimen writer), disguised signatures (written by the specimen writer) and simulated signatures (not written by the specimen writer). Results showed that, as a group, FHEs were significantly more confident at identifying writers’ genuine signatures than identifying writers’ disguised signatures or eliminating specimen writers from having authored simulated signatures. It is proposed that the difference in FHE confidence arises from the difficulty they have in deciding which alternative authorship explanation accounts for perceived combinations of similar and dissimilar features between specimen and questioned signatures.     

Sub-surface characterisation of latest-generation identification documents using optical coherence tomography

The identification of individuals, particularly at international border crossings, coupled with the evolving sophistication of identity documents are issues that authorities must contend with. Particularly, the ability to distinguish legitimate from counterfeit documents, with high throughput, sensitivity, and selectivity is an ever-evolving challenge.Over the last decade, an increasing number of security features have been introduced by authorities in identification documents. The latest generation of travel documents (such as passports and national ID cards) forego paper substrates for several layers of polycarbonate, allowing security features to be embedded within the documents. These security features may contain information at either the superficial and sub-surface levels, thus increasing the document’s resilience to counterfeiting.As the documents become harder to forge, so does the sophistication of forgery detection. There appears to be an unmet and evolving need to identify such sophisticated forgeries, in a non-destructive, high throughput manner.In this publication, we report on the application of optical coherence tomography (OCT) imaging on assessing security features in specimen passports and national ID cards. OCT allows sub-surface imaging of translucent structures, non-destructively enabling quantitative visualisation of embedded security features.     

Ink dating part II: Interpretation of results in a legal perspective

The development of an ink dating method requires an important investment of resources in order to step from the monitoring of ink ageing on paper to the determination of the actual age of a questioned ink entry. This article aimed at developing and evaluating the potential of three interpretation models to date ink entries in a legal perspective: (1) the threshold model comparing analytical results to tabulated values in order to determine the maximal possible age of an ink entry, (2) the trend tests that focusing on the “ageing status” of an ink entry, and (3) the likelihood ratio calculation comparing the probabilities to observe the results under at least two alternative hypotheses. This is the first report showing ink dating interpretation results on a ballpoint be ink reference population.In the first part of this paper three ageing parameters were selected as promising from the population of 25 ink entries aged during 4 to 304 days: the quantity of phenoxyethanol (PE), the difference between the PE quantities contained in a naturally aged sample and an artificially aged sample (R_NORM) and the solvent loss ratio (R%). In the current part, each model was tested using the three selected ageing parameters. Results showed that threshold definition remains a simple model easily applicable in practice, but that the risk of false positive cannot be completely avoided without reducing significantly the feasibility of the ink dating approaches. The trend tests from the literature showed unreliable results and an alternative had to be developed yielding encouraging results. The likelihood ratio calculation introduced a degree of certainty to the ink dating conclusion in comparison to the threshold approach. The proposed model remains quite simple to apply in practice, but should be further developed in order to yield reliable results in practice.     

论印刷文件鉴定标准

在分析印刷文件的印刷技术、印刷设备、文件形式、鉴定项目和鉴定技术的基础上,提出印刷文件鉴定标准体系应包含的内容及其构架,并对制定印刷文件鉴定标准中需要解决的问题进行探讨。     

论文件材料鉴定标准

通过阐述文件材料鉴定在文件鉴定中所处的地位,在分析文件材料鉴定特点的基础上,提出文件材料鉴定标准的框架模式和主要组成要素。     

Ink dating,part I: Statistical distribution of selected ageing parameters in a ballpoint inks reference population

The development of ink dating methods requires an important amount of work in order to be reliably applicable in practice. Major tasks include the definition of ageing parameters to monitor ink ageing. An adequate parameter should ideally fulfil the following criteria: it should evolve as a function of time in a monotonic way, be measurable in a majority of ink entries, be as accurate and reproducible as possible, and finally it should not be influenced too much by transfer and storage conditions. This work aimed at evaluating the potential of seven ageing parameters for ink dating purposes: the phenoxyethanol quantity, relative peak areas (RPA), three solvent loss ratios (R%, R%*, NR%) and two solvent loss parameters (R_NORM, NR_NORM). These were calculated over approximately one year for 25 inks selected from a large database to represent different ageing behaviours. Ink entries were analysed using liquid extraction followed by GC/MS analysis. Results showed that natural ageing parameters (NR% and NR_NORM) were not suitable ageing parameters for ink entries older than a few weeks. RPA used other compounds present in ink formulations in combination to PE in order to normalise the results. However, it presented particular difficulties as they could not be defined for all inks and were thus applicable only for 64% of the studied inks. Finally, the PE quantity, R% and R_NORM allowed to follow the ageing of the selected inks over the whole time frame and were identified as the most promising. These were thus selected to test three different interpretation models in the second part of this article. The possibilities and limitations of ink dating methods will be discussed in a legal perspective.