显微激光拉曼光谱法鉴别黑色圆珠笔油墨的初步研究

利用显微激光拉曼光谱法对纸张上黑色圆珠笔油墨字迹进行检验,结果表明 ,对不同的黑色圆珠笔油墨可以有效鉴别。该方法快速、简便、不破坏样品。     

拉曼光谱面扫描成像判断黑色圆珠笔交叉笔画书写先后顺序

目的建立一种灵敏、准确、无损的黑色圆珠笔交叉笔画书写顺序的检验方法。方法依据黑色圆珠笔油墨的同色异谱特征，利用显微共焦激光拉曼光谱仪进行面扫描成像分析检验。结果即使是差异很小的黑色圆珠笔油墨书写的交叉笔画，经过面扫描成像和图像处理后，也能看到先写笔道的连续性被后写笔道中断。结论拉曼光谱面扫描成像技术能有效判断黑色圆珠笔交叉笔画书写的先后顺序。     

GC-HPLC法考察圆珠笔字迹油墨厚度对溶剂挥发速率的影响

目的考察圆珠笔字迹油墨厚度对溶剂挥发速率的影响。方法采用GC/HPLC联用技术对不同时间、不同字迹油墨厚度在同种纸张上的圆珠笔油墨字迹中的溶剂、染料成分的定量分析。结果字迹油墨较厚的苯甲醇、苯氧基乙醇的含量随时间的变化比字迹油墨较薄的慢。结论字迹油墨的厚度对溶剂的挥发速率影响较大。     

光谱成像检验同种同色涂抹掩盖字迹研究

目的建立一种无损、灵敏、直观的同种同色涂抹掩盖字迹的显现方法。方法依据涂抹掩盖字迹油墨物质的同色异谱特征,利用可见光滤波型多光谱成像检验系统进行检验。结果黑色圆珠笔、蓝色圆珠笔、黑色签字笔和蓝色签字笔相互涂抹掩盖形成的同种同色涂抹掩盖样本,利用可见光滤波型多光谱成像检验系统进行检验,显效率分别为90.5%、69.1%、49.5%、78.6%,显现效果良好。结论多光谱成像技术可以显现同种同色涂抹掩盖字迹,且具有良好的显现效果。     

表面增强拉曼光谱对黑色圆珠笔快速鉴别的检测研究

目的 建立圆珠笔油墨的表面增强拉曼光谱分析方法,实现更加有效的圆珠笔样品种类区分。方法 选用纳米银胶体作为增强试剂,在785、633、514 nm 3种激发光波长下,分析检测市场上55支黑色圆珠笔的表面增强拉曼光谱,并通过将各激发光波长下的数据相结合来综合分析种类区分信息。结果 根据表面增强拉曼光谱图可有效区分出不同品牌圆珠笔油墨之间的差异。与增强前的拉曼光谱相比,增强之后的谱峰信号更强,在进行种类区分时更具说服力。785、633、514 nm 3种激发光波长的谱图信息相结合可获取更多有效的区分信息。结论 该方法能够有效鉴别不同品牌同一颜色的圆珠笔油墨,为司法鉴定中油墨成分的快速鉴别提供新思路。     

拉曼光谱成像技术检验朱墨时序中书写笔种类对检验结果的影响研究

目的考察在运用拉曼光谱阵列面扫描检验朱墨时序的方法中书写笔油墨种类对检验结果的影响。方法根据拉曼谱图的不同对搜集的188种书写笔（包括22种黑色圆珠笔,62种蓝色圆珠笔,62种黑色签字笔,42种蓝色签字笔）进行扫描并分类,采用拉曼光谱阵列面扫描技术对书写笔与同一印泥和印油形成的朱墨时序样本进行检验。结果 188种书写笔被分为4大类23小类,4类书写笔与印泥或印油形成的朱墨时序样本都得到了较好的检验结果。结论在本实验条件下,书写笔油墨种类对拉曼光谱阵列面扫描检验朱墨时序的检验结果没有影响。     

双溶剂提取法偏差范围的实验分析

目的双溶剂提取法是鉴定圆珠笔油墨字迹相对书写时间的方法之一,该方法简单有效,但在实际办案中发现,提取率的范围对数据的偏差范围有着直接影响。本文旨在通过实验分析偏差范围。方法通过对多种牌号的圆珠笔油墨新书写的字迹样本和自然老化样本进行平行实验。结果得到了不同提取率范围内的圆珠笔油墨提取率偏差范围。结论为双溶剂提取法鉴定圆珠笔油墨相对书写时间的界定提供了较为可靠的实验依据。     

圆珠笔油墨字迹书写时间鉴别的研究

圆珠笔油墨字迹书写时间的鉴别是摆在文件鉴定人员面前的棘手问题.本文作者借鉴国外的检验方法,经过近十年的探索,考查了各种因素的影响,研究出了适合我国国情的通过圆珠笔字迹油墨被溶解能力测试来确定其书写时间的鉴定技术,并且进一步发展了国外的检验方法,研制出了专用的检验器材,发明了模拟低温操作程序,使这一技术的适用范围更广.在有合适比对样本的情况下,可以准确鉴别落款时间在一年以上、怀疑书写时间在半年以内的可疑文件的真伪.     

透射光谱成像技术检验黑色签字笔涂抹掩盖字迹研究

目的 对透射光谱成像技术和反射光谱成像技术检验黑色签字笔间涂抹掩盖字迹进行比较研究,探寻一种无损、高效、直观的黑色签字笔涂抹掩盖字迹的显现方法,提高黑色签字笔间涂抹掩盖字迹显现效率。方法根据不同黑色签字笔油墨物质成分不同,不同物质对光的透射率各异的特征,在相同条件下使用反射光谱成像技术与透射光谱成像技术分别对多个黑色签字笔间涂抹掩盖字迹实验样本进行检验。本文将显现效果分为可显现和不可显现两类。分类标准为从未看过原字迹的非文检人员是否可以辨认出被涂抹掩盖字迹。结果 利用透射光谱成像检验系统检验黑色签字笔涂抹掩盖字迹样本,306个样本中,可显现的有231个,不可显现的75个,显效率为75.49%;反射光谱成像技术检验306个样本,其中可显现的有159个,不可显现的有147个,显现效率为51.96%。实验结果表明透射光谱成像检验黑色签字笔涂抹掩盖字迹的显现率高于反射光谱成像检验的检验。结论 除了无法显现原字迹与涂抹掩盖笔迹的油墨物质成分、浓度以及组成配比相同或相近的样本之外,透射光谱成像技术能检验常规的光谱成像技术无法显现的黑色签字笔间涂抹掩盖字迹,其显现效果和效率都优于反射光谱成像技术,是一种高效的显现方法 ,可以应用于刑事物证检验领域。     

文检仪显现同种同色掩盖字迹条件的初探

目的研究运用文检仪显现同种同色掩盖字迹的显出条件。方法以黑色签字笔为例,依据不同型号笔的油墨在不同光源下的荧光性质和红外吸收能力的差异,利用文检仪进行分析检验。结果只有在一定条件下被掩盖字迹才能被显出。结论在LUMI=IR红外荧光（兰光）下,只能显现激发荧光的油墨掩盖不能激发荧光的油墨的字迹和激发荧光能力弱的油墨掩盖激发荧光能力强的油墨的字迹;在红外吸收光和365nm长波紫外表面光下,只能显现颜色浅的油墨掩盖颜色深的油墨的字迹。     

Validation of LAB color mode as a nondestructive method to differentiate black ballpoint pen inks

Nondestructive digital processing methods such as lab color mode (available in Adobe Photoshop) are emerging as alternative methods for forensic document examiners to use when attempting to differentiate writing instrument inks. Although these techniques appear to be viable, little data currently exists regarding the known or potential error rates associated with these techniques. Without adequate data, the validity and reliability of these techniques, including lab color, can not be established. In an attempt to begin to address these issues, 44 black ballpoint ink pens were obtained and used to create 990 pen-pair samples for analysis using established lab color mode techniques. No erroneous findings of "different" were reported following the examination of the known pen-pair combinations in which the same pen was used to create the samples (n = 44). Of the remaining 946 samples, 737 pen-pair samples were differentiated using the lab color mode method, while 209 samples were unable to be differentiated and were recorded as either being "similar" (n = 153) or "unsure" (n = 56). Comparison of the lab color mode results with the results obtained through additional testing using traditional infrared reflectance and infrared luminescence test methods showed that lab color differentiated 102 pen-pair samples (11%; 102/946) that were not differentiated using a VSC-4C.     

Systematic analysis of bulk blue ballpoint pen ink by FTIR spectrometry

A classifying method on bulk blue ballpoint pen ink has been studied by Fourier transform infrared (FTIR) spectroscopy. By using this method, a total of 108 blue ink samples have been divided into two groups depending on their main component. Spectral characteristics of these inks such as frequency and absorbance are described by way of artificial intelligence of pattern recognition, and 35 subgroups from the 108 inks are distinguished by their correlation coefficient (lambda). Under heat or exposure to ultraviolet light a mode of change in the age of the inks has been obtained. This approach has provided a reliable and nondestructive method for the characterization of bulk ballpoint writing ink, and more importantly, it might be a basis for dating of the blue ballpoint pen ink.     

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.     

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).     

国产圆珠笔油墨字迹书写时间的鉴别

对国产圆珠笔油墨字迹书写时间的鉴别进行了实验研究,达到了检测速度快,实用性强,费用低的效果.     

Characterization and dating of blue ballpoint pen inks using principal component analysis of UV-Vis absorption spectra, IR spectroscopy, and HPTLC

The ink of pens and ink extracted from lines on white photocopier paper of 10 blue ballpoint pens were subjected to ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR), and high-performance thin-layer liquid chromatography (HPTLC). The R(f) values and color tones of the bands separated by thin-layer chromatography (TLC) analysis used to classify the writing inks into three groups. The principal component analysis (PCA) investigates the pen responsible for a piece of writing, and how time affects spectroscopy of written ink. PCA can differentiate between pen ink and ink line indicates the influence of solvent extraction process on the results. The PCA loadings are useful in individualization of a questioned ink from a database. The PCA of ink lines extracted at different times can be used to estimate the time at which a questioned document was written. The results proved that the UV-Vis spectra are effective tool to separate blue ballpoint pen ink in most cases rather than IR and HPTLC.     

A study to investigate the evidential value of blue and black ballpoint pen inks in Australia

The aim of this project was to investigate the evidential value of blue and black ballpoint pen inks in Australia. For this purpose, 49 blue and 42 black ballpoint pen inks, of different brands, models and batches, representative of those ballpoint pens available on the Australian market at the time of the study, were analysed by three techniques: filtered light examination (FLE); reflectance visible microspectrophotometry (MSP); and thin-layer chromatography (TLC). The results showed that the power of the individual techniques to discriminate inks between and within brands, models and batches varied, the most informative techniques being TLC>FLE>MSP. The greatest degree of differentiation was achieved when using a combined sequence of techniques, the discriminating power being 0.99 and close to 1 for blue and black inks, respectively (different brands and models). In respect to the discrimination between different batches of a same brand and model, it was shown that 14 out of the 33 pairs compared could be discriminated. Overall, this study confirmed the high value of the examination of inks when applied to ballpoint pens available in Australia, especially when a combined sequence of techniques is applied.     

Evaluation of principal components analysis with high-performance liquid chromatography and photodiode array detection for the forensic differentiation of ballpoint pen inks.

Inks from seven black and eight blue ballpoint pens were separated by a high-performance liquid chromatography (HPLC) method utilizing a photodiode array detection (PDA). A classifier flowchart was designed for the chromatographic data based on the presence or absence of certain peaks at different wavelengths to qualitatively discriminate between the inks. The same data were quantitatively classified by principal components analysis (PCA) to estimate the separation between a pair of classes of ink samples. It was found that the black ballpoint pen inks were discriminated satisfactorily utilizing two-dimensional data of the peak areas and retention times at the optimum wavelengths. The blue pens were discriminated by analyzing the chromatographic data at four different wavelengths simultaneously with a cross-validated PCA. The results of this study indicated that HPLC-PDA coupled with chemometrics could make a powerful discriminating tool for the forensic chemist, especially when analyzing extensive and/or complex data.     

书写材料的无损检验系统研究

本研究运用显微分光光度仪、文件检验仪和傅立叶变换拉曼光谱仪三种方法,分别对在中国市场上收集的不同厂家、牌号、型号的35种黑墨水、20种蓝黑墨水、22种蓝墨水、49种黑色墨水笔、30种蓝色墨水笔、45种黑色圆珠笔、和50种蓝色圆珠笔等七组样品进行非破坏检验。结果表明:(1三种非破坏检验方法都能单独对七组样品进行不同程度的鉴别,区分率在50%—94.4%之间;(2)三种方法联用后对黑墨水、蓝黑墨水、蓝墨水、黑色墨水笔、蓝色墨水笔、黑色圆珠笔和蓝色圆珠笔的区分率可分别提高到93.4%、97.3%、99.1%97.2%、97.2%、95.6%和91.8%。通过三种非破坏检验方法的联用,证明它们之间有较强的互补性,最大限度地提高了检验效应,可建立系统的非破坏检验方法。     

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.