Pen Inks Research Articles

Pen ink discrimination in handwritten documents using statistical and motif texture analysis : A classification based approach

Pen ink discrimination in handwritten documents using statistical and motif texture analysis : A classification based approach

Discrimination of Pakistani Fountain Pen Inks by Gas Chromatography-Mass Spectrometry (GC-MS).

In developing countries, the chances of fraud in written documents are comparatively high. Therefore, comparison of fountain pen inks is especially imperative in examination of forensic questioned documents. We have investigated the use of the gas chromatography-mass spectrometry technique in profiling and discrimination of fountain pen ink used in Pakistan for forensic purpose. The main purpose of this study was to discriminate different Pakistani fountain pen inks. The datum for Pakistani inks of fountain pen is not obtainable. In this research study, blue, black, and green colors fountain pen inks commercially used in Pakistan have been extracted from paper using micropunch and then investigated using the gas chromatography-mass spectrometry technique. Gas chromatography-mass spectrometry (GC-MS) was used to differentiate various brands of different colors of fountain pen inks based on their chemical composition. Molecular ion peaks for different components were obtained, and components were identified on the basis of detected ions. Results have been calculated and compared in terms of discriminating power (D.P.). The D.P. for blue, black, and green inks of fountain pen was 1.0 by using the gas chromatography-mass spectrometry technique.

Evaluation of Writing Performance for Different Types of Ballpoint Pen Ink by Acoustic Emission Sensing

During contact, deformation, and fracture of surface asperities between the friction surfaces of materials, acoustic emission (AE) waves are generated as the strain energy is released. By detecting the AE waves during friction using an AE sensor, the state of friction, wear, and lubrication between the friction surfaces can be measured and evaluated with high sensitivity. In this study, in order to establish a method for evaluating the writing performance of ballpoint pens by AE sensing, the measurement method was examined, and AE signal waveforms were analyzed. It was found that AE sensing can detect phenomena that do not appear as a change in frictional force during writing. In addition, frequency analysis of the AE signal waveforms revealed that differences in writing performance depending on the ink type of the ballpoint pen can be evaluated and interpreted.

Deciphering writings created with erasable/disappearing ink: A new method

A document examiner may face a large variety of cases pertaining to handwriting, ink, and paper examination. In cases of ink examination, issues may include identifying the ink as well as determining its permanency. These days there is an increasing number of cases pertaining to a cheque presented in the bank with an amount which was later denied by the drawee. Upon physical examination with the naked eye in daylight, the claim of the drawee appeared to be true – however, in case of doubt the fi nancial institutions dealing with such transactions, including banks, send the document for examination. It has been observed that a good number of ink pens are available in the market whose writings get invisible after some time ranging from hours to days. These types of writing pens are manufactured for fabric/garment manufacturing companies to mark the fabric for tailors, instructing them where cuts should be made. These marking pens are used now a day quite frequently throughout the world by the criminals to write the cheque and to later deny the amount on the cheque because of the fact the writings written with such inks fade or become invisible. Thus, the document is sent for examination. A number of methods have been reported to deal with the problem of decipherment of such writings but in present study very simple and readily accessible technique has suggested to visualise the writings which disappeared on heating. In this work, the disappeared writings which were produced by the PILOT FriXion erasable ink pen are made visible by cooling the document containing the aforesaid writings in a freezer of an ordinary refrigerator.

New Trends in Analytical Chemistry for the Examination and Interpretation of Traces of Crimes

Forensic sciences are generally described as the application of the scientific method to the analysis of traces in order to identify the authorship and materiality of a crime . Forensic scientists evaluate different types of materials, and the type of scientific method and techniques employed depend on the questions to be answered within a given context . Forensic chemistry is one of the most far-reaching areas within the forensic science field. With the increase in technology and the development of analytical techniques, chemistry has been used more and more to elucidate legal controversies. Therefore, knowledge in chemistry is indispensable to solve crimes. In this letter, the applications of analytical chemistry will be discussed within emerging forensic themes: the determination of the origin of seized drugs (chemical profiling), the investigation of document fraud, and the valuation analysis of pieces of art. Chemical profiling consists of a series of chemical analyses that provide the concentration of the components present in the seized drugs, present as major or minor components, or event those present only in trace levels. Using different analytical methods, complex chemical profiles are obtained for each drug sample analyzed, giving these samples a chemical “signature” based on the presence of impurities of natural origin. and added diluents/adulterants. Therefore, such studies generate relevant data that make it possible to establish connections between samples and materials of different seizures, classifying them into chemically correlated groups. Through these connections, it is possible to establish specific links among suppliers, drug dealers, and users, designing distribution network patterns and providing subsidies for the identification of the origin of the drug, including its geographical origin. Another striking forensic application of analytical chemistry is age determination and the authenticity of papers and inks. Once an ink is deposited on a support (paper), it is exposed to air, light, and moisture, and the following physical–chemical processes occur: coloration degradation, solvent evaporation, and hardening (polymerization) of the resins. These processes have been used in the complex task of determining the absolute or relative (comparative) age of manuscripts on paper. The largest number of publications refer to ballpoint pen inks. Ezcurra and collaborators published a comprehensive review on the dating of paints by modern instrument writers. Analytical paint dating exams essentially consist of quantifying how paint components vary over time. Last but not least, the authentication of pieces of art used as a tool to fight crime is a recent area of activity of analytical chemistry in Brazil. Operation Lava Jato shed light on the possibility that criminal use of the art market is a widespread method among agents of corruption and that it is much more complex and structured than previously thought. It is up to criminal experts to determine the authenticity of a piece of art. In general, the analytical investigations are guided by the identification and quantification of substances used in the production of the art piece, using non-destructive methodologies, such as Raman spectroscopy.

Raman spectroscopy with self-organizing feature maps and partial least squares discriminant analysis for discrimination and source correspondence of red gel ink pens

• Novel study reporting on discrimination and source correspondence of red gel ink using Self-Organizing Feature Maps (SOFM) and Partial Least Square in tandem with non-destructive techniques of Raman Spectroscopy. • Unsupervised Self-Organising Feature Maps (SOFM) was initially used for data exploration. • Partial Least Square Discriminant Analysis was used as classification model. • Correct prediction rate (100%) for all unknown samples according to specific type of colorants using the trained PLS-DA model.

Evaluation of the performance of erasable marker pen ink for the development of indentations on documents upon surface charging by electrostatic detection device

Indented impressions can be left on the surface beneath a document when it is written on. In the absence of this document, electrostatic detection devices can be used to reveal the underneath previously written information. However, there are instances where the toner used to develop these indentations has to be substituted with alternative application, under unexpected circumstances, such as the supply chain disruption during the ongoing global pandemic. This study aimed to verify the use of erasable marker pen ink as an alternative application for the development of indentations. The procedure was optimized and evaluated, and its performance in deciphering indented impressions from 11 different underlying surfaces was compared to a conventional electrostatic detection device that applied toner to develop indentation. Electrostatic device with toner application using cascade developer method has successfully developed indented impressions from all surfaces, except for the coated glossy paper. In contrast, the application of erasable marker pens revealed indentation successfully from not only the coated glossy paper but also six other common writing surfaces. While the toner is a reliable application for deciphering indentations, the application of erasable marker ink pen can be used in the event when toners are unavailable but also on surfaces such as glossy paper, where application of toners to develop indentation may not provide satisfactory results.

Identification of Fountain Pen Ink Properties Which Determine the Amount Put on Paper

Identification of Fountain Pen Ink Properties Which Determine the Amount Put on Paper

Classification of ballpoint pen inks based on selective extraction and subsequent digital color and cluster analyses.

Here, we propose a novel approach to the classification of blue ballpoint pen inks based on a combination of selective extraction of coloring components from a paper carrier, digital color analysis (DCA) of the remaining traces, and hierarchical cluster analysis of DCA results. Since most documents of high importance are still produced in hard copies, the proposed method, being highly time- and cost-efficient, could be a significant contribution to forensic science in the field of authenticating handwritten documents. Several commonly used solvents were applied in parallel as extractants to the replicate strokes produced by each pen. It turned out to be possible to limit the number of extractants required for an unambiguous classification to three. We have shown that the optimal descriptor for agglomerative clustering is the colorimetric distance between the original and extracted ink traces in the RGB color space. Five separate clusters of inks that are independent of sample storage temperature were obtained from a set of 16 different pens. This conclusion was further confirmed by the analysis of principal components. The developed DCA-based data processing pipeline outperformed the clustering based on the data of high-performance liquid chromatography in terms of versatility providing a more informative analysis with respect to the inks based on the phthalocyanine dyes.

Forensic Discrimination of Blue Ballpoint, Gel and Oil-Gel Pens: Application of Chemometrics to ATR-FTIR Data

The combination of advanced techniques with multivariate analysis methods are being used with great confidence by forensics experts due to their high precision and accuracy. The prime objective of present work was to explore the potential of chemometric tools in discriminating and predicting the blue pen inks when applied on Attenuated total reflectance Fourier transform infrared (ATR-FTIR) data of pen strokes of different brands and models commercially available in Pakistani markets. The pen strokes on fine A4 paper and recycled A4 paper were obtained from 86 samples including ballpoints, gel, oil- gel and roller ball pens. ATR-FTIR spectra were first characterized for different functional groups present in ink pigments however, they were apparently indistinguishable having some common functional groups. After spectra preprocessing the principal component analysis (PCA) and agglomerative hierarchical cluster analysis (AHC) showed that pen strokes could be distinguished. Both PCA and AHC analyses showed that ballpoints and gel pen could be discriminated and grouped separately. PCA analyses also showed the discrimination between local and foreign brands of ballpoints. Finally, classification method partial least squares-discriminant analysis (PLS-DA) was successfully applied for the classification and subsequently for the identification of type of pen used in personnel’s signature to mimic a forensic case. To evaluate PLS-DA classification performance, the classification parameters such as sensitivity, specificity, accuracy and precision were also derived from confusion matrix. Overall, this work emphasized the worth of multivariate analysis in classification and prediction of type of writing pen in a document as a forensic study.

Comparative application of sem and fe-sem in the determination of the sequence of crossing of printer ink lines with writing pen inks

Comparative application of sem and fe-sem in the determination of the sequence of crossing of printer ink lines with writing pen inks

Evaluating the effectiveness of optical techniques for establishing the sequence of inkjet printed text with writing pen ink lines

Evaluating the effectiveness of optical techniques for establishing the sequence of inkjet printed text with writing pen ink lines

Chemometric Approaches in Questioned Documents

Questioned documents comprehend analysis of identity theft, forged signatures or texts, documents alterations and falsification of security documents or banknotes. Questions involving inks or paper require chemical analysis, and multivariate analysis or chemometrics has been an emerging tool for data evaluation and interpretation after instrumental data collection in this area. The goal of this study is to identify previous articles that applied multivariate analysis within questioned documents for forensic purposes. The search for articles was performed in four databases (Google Scholar, Science Direct, Pubmed and Scopus). Sixty studies, published in the last ten years, were selected. Thirty-four articles described pen inks analysis; fourteen articles comprehended printed documents studies; eight articles evaluated paper analysis, and four articles included banknotes analysis. Spectroscopy, mass spectrometry, chromatography, thermo gravimetric analysis and multivariate image analysis were the analytical methods applied to collect chemical data. Chemometrics methods included mainly unsupervised pattern recognition techniques, regression methods, and supervised pattern recognition techniques, amongst other methods. This review summarized and discussed multivariate analysis techniques applied in different questioned documents sub-areas, highlighting the importance of this knowledge for forensic analysts. In addition, it shows new research topics such as different printing and pen inks, papers and security documents analysis herein not included.

Parmigianino’s Bitch

Parmigianino’s Bitch

Combination of a Green and a Traditional Method for Estimating Relative and Absolute Ink Age: A Case Study of Ballpoint Pen Ink Dating in Vietnam.

The dating of ink in questioned documents remains a significant challenge in forensic investigations in Vietnam and other countries. Many forensic examination methods have been usually applied to ensure the highest accuracy of the assessment results while maintaining high environment awareness. In this study, paper characteristics were physically tested to confirm source similarity, and the relative ink dating was established by high-performance thin-layer chromatography (HPTLC). Absolute ink dating by solvent and dye identification was performed by Raman spectrometry—a green technique, using a time-dependent degradation model for crystal violet and the comparison between 2-phenoxyethanol peak intensities. We found that the relative dating of the questioned document was 14 ± 3 months lesser than that of the reference samples, i.e., the absolute age of the questioned samples was estimated to be 24 ± 3 months. The combination of the conventional HPTLC method with the dynamic crystal violet degradation Raman model provides promising results for relative and absolute ink dating of ballpoint pens, which can be applied for documents written 1–15 years prior to the time of examination. The combination of the abovementioned methods demonstrated an acceptable error margin, affording highly practical applications in modern forensic science.

Manufacturing a Plotter Printer with Computer Numerical Control Based Pen Ink Using CoreXY Mechanisms

In the process of printing images, a high-quality plotter printer is required to obtain better printed images. This causes the costs incurred to purchase a plotter printer become even higher along with the quality of the printout. In addition, the use of original plotter printer ink is significantly more expensive than that of the non-original ink. Therefore, this paper proposes a pen based computer plotter printer design using the CoreXY framework. This framework is based on a 2D in-axis motion control technique using a single continuous belt for both axes. To evaluate the performance of the proposed design, the level precision for vector and raster modes are measured using the Mean Absolute Percentage (MAPE). Based on the results of precision measurements, it was found that the printer prototype designed to produce high-precision images with affordable pen ink costs and can process digital instructions from a computer using Computer Numerical Control (CNC).

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.

Direct Coating Pen Ink Carbon on a Carbonized Melamine Sponge as a Flexible Free-Standing Electrode

A facile and environmental-friendly method is developed to enhance the mechanical properties and electrochemical performance of a carbonized melamine sponge (CMS) via commercial pen ink coating. Th...

Hybrid ternary rice paper/polypyrrole ink/pen ink nanocomposites as components of flexible supercapacitors

The rapid development of the portable and wearable devices has inspired the ever-growing pursuit of flexible energy storage equipment which can power these devices. Here, rice paper (RP) was integrated with a homemade LGS-polypyrrole (LGS-PPy) ink and commercial pen ink in order to construct a flexible electrode of a supercapacitor via a facial dip-coating method. The obtained RP/LGS-PPy ink/Pen ink composites showed a high areal specific capacitance of 1568 mF/cm2 at 0.2 mA/cm2, owing to the uniform deposition of a LGS-PPy layer which was covered by the pen ink coating. Furthermore, the assembled symmetric supercapacitor fabricated from the RP/LGS-PPy ink/Pen ink electrode exhibited impressive electrochemical performances in terms of specific capacitance (317.5 mF/cm2 at 2 mA/cm2), power density (846 μW/cm2 at the energy density of 23.5 μWh/cm2), and life times (82.1% capacitance retention after 5000 cycles). In addition, the capacitance of the as-prepared device remained essentially unchanged even after bending at 180°, thus demonstrating this device's outstanding flexibility. The low cost of raw materials, robust fabrication strategy as well as the moderate performances make the RP-based supercapacitor a promising candidate for future flexible energy storage devices.

VSC®-8000/HS- A Robust Tool for Differentiation of Overlapped Black Pen Inks in Fraudulent Documents

Contemporary advancement and digitalization of technology has made analysis of ink extremely challenging. Selecting the best technique for ink analysis is the need of the hour. The latest version of Video spectral comparator i.e. VSC®- 8000/HS has a vast horizon of features such as multi-spectral light sources, database of currencies and passports of different countries and even micro-spectrometer for composition analysis. The present study focuses on determining the efficacy and capability of light sources of varied spectrum and spectrometer for the examination of black ball, gel and fountain pen inks particularly in questioned under scrutiny written with hand. VSC®-8000/HS have demonstrated to be substantially efficient, robust and an exhaustive nondestructive technique for analysis of documents serving as evidence which have been manipulated including obliterations, additions or overlapping of two or more black ball or fountain pen inks. However, the technique did not provide effective results for black gel pen inks in contrast to black ball and fountain pen inks. Nonetheless, it can effectively harmonize with the standard workflow of a forensic document examiner to ensure qualitative and quantitative facts and figures for the expert testimony.