Forensic Document Examiners’ Skill in Distinguishing Between Natural and Disguised Handwriting Behaviors

Abstract: Disguised handwriting is problematic for forensic document examiners (FDEs) and attracts higher misleading and inconclusive rates on authorship opinions than does genuine writing (Found B, Rogers D, International Graphonomics Society, 2005). There are currently no published empirical data on FDEs’ expertise in distinguishing between natural and disguised writing behavior. This paper reports on the skill of FDEs for determining the writing process of 140 pairs of natural and disguised writings and compares their results with those of a control group of laypeople. A significant difference was found between the examiner and lay group. FDEs’ expertise is characterized by their conservatism, where FDEs express a higher proportion of inconclusive opinions (23.1% for FDEs compared to 8.4% for the control group). This leads to the FDEs expressing a smaller percentage of misleading responses when calling writings as either naturally written or disguised (4.3% for FDEs compared with 12.2% for the control group).     

Using automated comparisons to quantify handwriting individuality

The proposition that writing profiles are unique is considered a key premise underlying forensic handwriting comparisons. An empirical study cannot validate this proposition because of the impossibility of observing sample documents written by every individual. The goal of this paper is to illustrate what can be stated about the individuality of writing profiles using a database of handwriting samples and an automated comparison procedure. In this paper, we provide a strategy for bounding the probability of observing two writers with indistinguishable writing profiles (regardless of the comparison methodology used) with a random match probability that can be estimated statistically. We illustrate computation of this bound using a convenience sample of documents and an automated comparison procedure based on Pearson's chi-squared statistic applied to frequency distributions of letter shapes extracted from handwriting samples. We also show how this bound can be used when designing an empirical study of individuality.     

Identification of the Class Characteristics in the Handwriting of Polish People Writing in English

Abstract: An investigation was carried out to identify the class characteristics of Polish people writing in English and to specifically identify those characteristics that separate Polish handwriting from English handwriting. In the first stage, 40 Polish and 40 English handwriting samples were collected and systematically examined. In total, 31 features were identified that occurred in ≥25% of the Polish handwriting samples and therefore considered class characteristics. Of these, chi‐square analyses identified 21 class characteristics that occurred significantly more in Polish compared to English handwriting. Twenty‐one of the class characteristics in the Polish handwriting had similar constructions to the copybook pattern thus supporting the theory that class characteristics frequently stem from the taught writing system. In the second stage, an algorithm was developed using seventeen of the class characteristics that successfully discriminated between a further 13 Polish and 12 English handwriting samples.     

Kinematics of Signature Writing in Healthy Aging

Forensic document examiners (FDE) called upon to distinguish a genuine from a forged signature of an elderly person are often required to consider the question of age‐related deterioration and whether the available exemplars reliably capture the natural effects of aging of the original writer. An understanding of the statistical relationship between advanced age and handwriting movements can reduce the uncertainty that may exist in an examiner's approach to questioned signatures formed by elderly writers. The primary purpose of this study was to systematically examine age‐related changes in signature kinematics in healthy writers. Forty‐two healthy subjects between the ages of 60–91 years participated in this study. Signatures were recorded using a digitizing tablet, and commercial software was used to examine the temporal and spatial stroke kinematics and pen pressure. Results indicated that vertical stroke duration and dysfluency increased with age, whereas vertical stroke amplitude and velocity decreased with age. Pen pressure decreased with age. We found that a linear model characterized the best‐fit relationship between advanced age and handwriting movement parameters for signature formation. Male writers exhibited stronger age effects than female writers, especially for pen pressure and stroke dysfluency. The present study contributes to an understanding of how advanced age alters signature formation in otherwise healthy adults.     

书写能力的结构

目的提出人的书写能力由基础因子构成的假说。方法根据因子说,不同字的笔顺可能相关。以反犬旁、山字为目标字,收集799份有效实验样本,分性别检验实验样本中2个目标字的笔顺是否相关。结果统计检验表明反犬旁笔顺与山字笔顺相关（p〈0.01）,用一个笔顺在另一个笔顺出现的条件下的出现率与它的出现率之比测定它们相关性的大小,最高的比值为3.65。结论证实了人的书写能力由基础因子构成的假说,这个假说可以作为笔迹比较的理论基础。     

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。     

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.     

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。     

Analysis of Pigmented Inkjet Printer Inks and Printed Documents by Laser Desorption/Mass Spectrometry*,†

Abstract: Anyone with a computer, scanner, and color printer has the capability for creating documents such as identification cards, passports, and counterfeit currency. Laser desorption mass spectrometry (LDMS) has been demonstrated as a powerful tool for colorant analysis. Inkjet printers are now moving largely toward the use of pigments as colorants; their insolubility makes analysis by simpler methods such as thin‐layer chromatography no longer an option. Recent developments in pigmented inkjet printer inks, such as gloss optimizers that coat pigment particles, may prohibit colorant analysis by LDMS. We demonstrate here that pigments used in inks from two Epson printers can be detected and analyzed by LDMS. Also, LDMS spectra of various colors created using a 4‐cartridge (cyan/magenta/yellow/black, CMYK) inkset are evaluated, to begin to develop an approach for unraveling LDMS data from real samples, to determine the number of inks used by a printer, and the chemical composition of the colorants.     

竖心旁笔顺判断方法

收集150份实验笔迹样本,由书写人报告样本字中竖心旁的笔顺。实验样本中出现了3种竖心旁的笔顺,在此基础上归纳了3种笔顺的判断规则。     

Altered handwriting suggests cognitive impairment and may be relevant to posthumous evaluation

Judging the validity of a disputed will is complex; however, one of the main issues is what the mental status of the testator was at the time of the will. If the will is handwritten, a handwriting analysis can provide information on the mental status of the testator. We tested how two writing parameters (the "writing score," a novel evaluation scale that we previously described, and the percentage of spelling mistakes) are capable to identify cognitively impaired persons. These parameters are especially helpful because they can be used to evaluate the mental status of a deceased person. We found a significant correlation between either parameter and established scales of neuropsychological evaluation (Mini Mental State Examination and Milan Overall Dementia Assessment scale). Specifically, a poor score on either parameter reliably identified a compromised cognitive status. These may represent helpful additions to existing techniques in posthumously identifying persons with severe cognitive impairment.     

Identification of colorants in pigmented pen inks by laser desorption mass spectrometry

Pigments are rapidly replacing dyes as colorants in pen and printer inks, due to their superior colors and stability. Unfortunately, tools commonly used in questioned document examination for analyzing pen inks, such as TLC, cannot be used for the analysis of insoluble pigments on paper. Laser desorption mass spectrometry is demonstrated here as a tool for analyzing pigment-based pen inks. A pulsed nitrogen laser can be focused onto a pen stroke from a pigmented ink pen on paper, and positive and negative ions representative of the pigment can be generated for subsequent mass spectrometric analysis. Targeted pens for this work were a set of Uni-ball 207 pigmented ink pens containing blue, light blue, orange, green, violet, red, pink, and black inks. Copper phthalocyanine was identified as the pigment used to make both blue inks. A mixture of halogenated copper phthalocyanines were identified in the green ink. Unexpectedly, the pink ink was found to contain a red pigment, Pigment Red 12, treated with a mixture of water-soluble dyes. Each sample yielded ions representative of the pigments present.     

An insight into forensic document examiner expertise for discriminating between forged and disguised signatures

It has previously been shown that forensic document examiners (FDEs) have expertise in providing opinions about whether questioned signatures are genuine or simulated. This study extends the exploration of FDE expertise by evaluating the performance of eight FDEs and 12 control subjects at identifying signatures as either forgeries or the disguised writing of a specimen provider. Subject eye movements and response times were recorded with a Tobii 1750 eye tracker during the signature evaluations. Using a penalty scoring system, FDEs performed significantly better than control subjects (t = 2.465, p = 0.024), with one FDE able to correctly call 13 of the 16 test stimuli (and three inconclusive calls). An analysis of eye movement search patterns by the subjects indicated that a very similar search strategy was employed by both groups, suggesting that visual inspection of signatures is mediated by a bottom up search strategy. However, FDEs spent greater than 50% longer to make a decision than the control group. The findings are suggestive that for some stimuli FDEs can discriminate between forgeries and disguises, and that this ability is due to a careful inspection and consideration of multiple features within a signature.     

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.