Ink Samples Research Articles

Screen printing of catechu (Senegalia catechu)/guar gum based edible ink for food printing and packaging applications

Senegalia catechu is an excellent substitute for synthetic pigments; nevertheless, it is necessary to mix pigment with binder and functional agents. In this study, Senegalia catechu pigment (SNC), as the main constituent-based edible inks, was prepared. Calcium carbonate (CC) as a colour enhancing agent and guar gum (GM) as a binder were incorporated in concentrations of 0.2, 0.5, and 1 %, and its influence on edible ink's solid content, colour, rub resistance, light fastness, and antioxidant activity was assessed. All samples of the edible ink have demonstrated excellent printing effects and visual recognition. The SNC/CC/GM-3 edible ink has shown a smooth surface, the highest colour value of 36.48 ± 0.23, rub resistance of 0.96 ± 0.01, and light fastness of 1.02± 0.21 among all the synthesized inks. This ink was also applied through screen printing on apple, mango, cookie, edible cup, etc. We believe that Senegalia catechu-based edible ink can be used for direct printing on food products and non-food items.

Synthesis And Structural Feasibility Of Photonic Materials

Aim: Studying the optical-thermal dependence of liquid crystal based on the quantity data of image texture is essential to get more information accurately Background: In this research, the optical-thermal dependence of chiral nematic liquid crystals ink sample was investigated based on the sample's texture and colour changes at various temperatures. Objective: The structural and optical characteristics of ZnO thin films are investigated in this study. While spinning at 4000 rpm for 30 seconds at room temperature, the zinc oxide solution was spun onto a pre-cleaned, glass substrate, creating the desired layer thickness. method: This was followed by annealing at 150°C-600°C in 50°C steps, which was carried out on the samples. An ultraviolet-visible spectrophotometer and a scanning electron microscope were used to analyse the optical properties of this thin coating. Method: This was followed by annealing at 150°C-600°C in 50°C steps, which was carried out on the samples. An ultraviolet-visible spectrophotometer and a scanning electron microscope were used to analyse the optical properties of this thin coating. Result: Zinc oxide's optical band gap was determined by measuring its optical transmittance, reflectance, and absorbance. Photonic crystals can exhibit relevant optical properties when transmitting or reflecting a light beam. conclusion: In particular, in a two-dimensional photonic crystal, the reflective properties can be of interest and consequently optimized for different technological applications such as tuneable laser cavities, photovoltaic solar systems, and selective high reflection mirrors, among many others. Conclusion: In particular, in a two-dimensional photonic crystal, the reflective properties can be of interest and consequently optimized for different technological applications such as tuneable laser cavities, photovoltaic solar systems, and selective high-reflection mirrors, among many others.

Characterizing different types of black fountain pen ink using the chemical approach

Fountain pen ink contains dyes, pigments, or nanoparticles as colorants; water and ethylene glycol or an organic solvent as the vehicle. The dyes in fountain pen ink are usually negatively charged acid dyes. In this study, various types of black fountain pen ink (5 dye-based and 5 nanoparticle-based) were investigated by ultraviolet–visible (UV–Vis) absorption spectroscopy, Ion Pair High Performance Liquid Chromatography Diode-Array Detector (IP-HPLC-DAD), Matrix Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS), and Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-Q/TOF-MS) analysis. UV–Vis spectroscopy of fountain pen ink samples showed different profiles despite their similar color. MALDI-TOF-MS analyses successfully differentiated 10 of the inks. Nanoparticle-based ink, which is usually darker than dye-based ink, showed the same UV absorption at 240 nm. The use of LC-Q/TOF-MS, however, allowed the 5 dye-based fountain pen ink samples to be differentiated from one another. On the basis of the combined results of all analytical methods mentioned above, the discriminating power values were 0.71–1.00. Among them, MALDI-TOF-MS could successfully distinguish fountain pen ink samples with similar black colors and provide an easy analytical approach for the differentiation and identification of various types of fountain pens.

Experimental investigations into additive manufacturing of styrene-ethylene-butylene-styrene block copolymers using solvent cast 3D printing technique

PurposeThis paper aims to discuss the successful 3D printing of styrene–ethylene–butylene–styrene (SEBS) block copolymers using solvent-cast 3D printing (SC-3DP) technique.Design/methodology/approachThree different Kraton grade SEBS block copolymers were used to prepare viscous polymer solutions (ink) in three different solvents, namely, toluene, cyclopentane and tetrahydrofuran. Hansen solubility parameters (HSPs) were taken into account to understand the solvent–polymer interactions. Ultraviolet–visible spectroscopy was used to analyze transmittance behavior of different inks. Printability of ink samples was compared in terms of shape retention capability, solvent evaporation and shear viscosity. Dimensional deviations in 3D-printed parts were evaluated in terms of percentage shrinkage. Surface morphology of 3D-printed parts was investigated by scanning electron microscope. In addition, mechanical properties and rheology of the SC-3D-printed SEBS samples were also investigated.FindingsHSP analysis revealed toluene to be the most suitable solvent for SC-3DP. Cyclopentane showed a strong preferential solubility toward the ethylene–butylene block. Microscopic surface cracks were present on tetrahydrofuran ink-based 3D-printed samples. SC-3D-printed samples exhibited high elongation at break (up to 2,200%) and low tension set (up to 9%).Practical implicationsSC-3DP proves to be an effective fabrication route for complex SEBS parts overcoming the challenges associated with fused deposition modeling.Originality/valueTo the best of authors’ knowledge, this is the first report investigating the effect of different solvents on physicomechanical properties of SC-3D-printed SEBS block copolymer samples.

A Model Iron Gall Ink: An In-Depth Study of Ageing Processes Involving Gallic Acid

Iron gall inks have been among the most used writing materials after carbon black, thus representing an important element of the historical and artistic heritage of our society. Crucially, the preservation of manuscripts and drawings is influenced by the presence of these inks, leading to conservation issues related to paper degradation and text fading. Besides all the advances obtained in paper conservation, the study of iron gall ink's behaviour and ageing is still an important topic, which requires investigation through an accurate molecular characterisation to produce reliable models. In the present work a micro-destructive method based on liquid chromatography techniques (HPLC-DAD and HPLC-ESI-Q-ToF) has been optimised starting from a model gallic acid-based ink. An in-depth study of the behaviour of the ink in time was performed by natural and artificial ageing tests, monitored by colorimetry, showing the autoxidation of gallic acid to ellagic acid in the prepared mock-ups. The effect of relative humidity on ageing processes was also evaluated, allowing us to determine different intermediates depending on the environmental conditions. Finally, the analytical method developed was then successfully applied for investigating 19th-20th century historical ink samples, where one of the identified ageing markers was detected, besides the expected gallic and ellagic acids.

Development of a water-based functional additive by using isobornyl acrylate copolymer to improve ink-adhesion on untreated polypropylene surfaces: A comparative approach

The good barrier and hot-fill properties of polypropylene (PP) films and sheets make packaging industries advantageous. However, printing over a PP substrate is a major issue encountered in the packaging industry. The present study intends to prepare, characterise, and compare isobornyl acrylate (IBOA)-co-acrylic acid (AA) and isobornyl acrylate (IBOA)-co-methacrylic acid (MAA) based non-halogenated functional additives by using oil in water emulsion processes. The bornyl group of IBOA helps in enhancing molecular bonding with the polypropylene (PP) surface. The various properties of these synthesised functional additives were characterised using dynamic light scattering-particle size and zeta potential analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), and gel permeation chromatography (GPC). The adhesion of these functional additive incorporated ink samples on different untreated PP surfaces was compared using the cross-cut adhesion test. The methacrylic acid based functional additive shows better adhesion properties as compared to acrylic acid.

Analysis and chemical imaging of blue inks for the investigation of document forgery by XPS

Any written document whose originality or authenticity is disputed is defined as a ‘questioned document’. Forensic document examiners deal with a variety of documents whose authenticity needs to be verified. Due to the increasing sophistication of forgery and document modification techniques, physical and chemical analysis of the inks involved is a common part of their forensic analyses. X-ray photoelectron spectroscopy (XPS) is an innovative technique for ink analysis, which does not require any sample preparation, and can easily detect chemical differences within reasonably short durations. Furthermore, it is non-destructive to the evidence. This study aimed to demonstrate the application of XPS to forensic analyses of ink evidence from liquid pens. In the present study, five different blue liquid pens were analysed by XPS, and their elemental composition was determined. Then, chemical imaging was done by XPS on the changed and added areas. In addition, mapping was also applied for blind testing of different pens and the same pen. Herein, XPS mapping was realised with a fixed spot size and step size of 100 µm for the acquisition of spectra at each pixel. Each of the blue ink samples in this study was shown to have distinct chemical compositions. Moreover, the chemical imaging feature of XPS using principal component analysis (PCA) was also able to detect if the text in the documents was altered with another pen with ink of the same colour. Finally, blind testing of samples written with either different or the same pen was realized. These preliminary results showed that the XPS can be an effective tool for the forensic investigation of documents.

Effect of natural surfactant on the performance of reduced graphene oxide conductive ink

Conductive ink with stable dispersion and excellent printing properties can be produced using graphene-based nanomaterials and suitable solvents for flexible printed electronics applications. Eco-friendly water-based inks can be used as an alternative to organic solvents-based inks to minimize environmental impacts. Graphene oxide (GO) nanofillers can form stable aqueous dispersions and can be produced in bulk quantities using chemical exfoliation methods. Hence GO nanofillers can be used as a filler to produce water-based conductive ink for printed electronics applications. However, the higher surface tension and lower stability are major drawbacks which limit its printing properties. Natural surfactants can minimize these issues to ensure smooth printing with a higher shelf life as compared to harmful synthetic surfactants. This study aimed to investigate the role of natural-based surfactants such as gum arabic, cellulose nanocrystals and alkali lignin in producing stable and high performing water-based GO ink. The prepared ink samples were characterized for their wetting properties, printability, and storage time. The ink was also investigated for structural, functional groups, and stability. The printed patterns were investigated for morphological and electrical properties. The results from study indicate that the GO with alkali lignin surfactant gives long-term stability and better printing properties compared to other samples. The printed pattern after thermal reduction was found to have a conductivity of 833 S/m, which was reduced by only 2.6% after 100 bending cycles, whereas the electrical conductivity was reduced by only 0.6% after 10 rolling cycles indicating a great potential to be used in flexible electronic devices.

Characterization and discrimination of volatile compounds in gel-pen ink via headspace-gas chromatography-ion mobility spectrometry combined with chemometric strategies

Handwriting is usually suspected of any alterations or falsifications in litigation activities. Hence, handwriting verification of documents is an important part to solve legal dispute caused by parties in the field of forensic science. For the first time, headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was applied for the reliable analysis of the distinguishment of sophisticated compositions in ink samples. The volatile organic compounds of seven common ink species were investigated. Topographic photographs of HS-GC-IMS provided the differentiation of various gel-pen inks with quickly and intuitively. Based on visual assessments and precise qualitative analysis, a total of 95 selected volatile compounds were characterized on feature map. Ketones, eaters and alcohols were the significant components from the recognizable fingerprint gallery in HS-GC-IMS. Chemometric models, such as Principal component analysis (PCA), heatmap and Hierarchical cluster analysis (HCA), clearly identified the differences of volatile substances and discriminated the origins of gel-pen ink samples. Therefore, HS-GC-IMS as an effective and accurate comprehensively instrument was appropriate for the discrimination of various gel-pen ink species, which would contribute to establish the corresponding ink database and further explain the document dating in forensic science.

Comparative analysis of aged documents by desorption electrospray ionization-Mass spectrometry (DESI-MS) imaging.

Document dating is an important and challenging task in the field of forensic science. With the development of analytical techniques, related methods are emerging for document dating studies. Desorption electrospray ionization-mass spectrometry (DESI-MS) is an ambient ionization-MS technique that has been applied in the forensic discrimination of inks. This study focused on utilizing DESI-MS to distinguish between ink entries of different ages. Blue ballpoint ink and black gel ink samples were artificially aged by heat and light exposure and then screened by DESI-MS in the positive ion mode, with a methanol-water-formic acid solution (90:10:0.1%, v/v/v) as the desorption solvent. As a result, the artificially aged ink samples were directly differentiated from the reference ones in the chemical images of age-dependent compounds such as basic dyes or polyethylene glycol derivatives. The amount of ethoxylated fatty amine surfactants in copy paper was also found to decrease after artificial aging. Moreover, this method enabled us to visualize the differences between the composition of naturally aged and fresh ink samples. It has been proven to cause no apparent destruction of the samples. The identification of chronological changes in document materials suggests that the DESI-MS method is a promising approach for relative document dating.

Trends of Forensic Analysis of Pen Ink Using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) Spectroscopy

Many articles have been published on ink analysis to assist Forensic Document Examiner (FDE) in examining questioned documents. Ink analysis encountered about 45% of ballpoint and 24% of gel pen in forensic cases. Typically, ink samples found on the documents are limited to small quantities, requiring non-destructive techniques to preserve the evidence. Previous studies on ink analysis cover about 80% of spectroscopy techniques, including the Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR). FDE prefers ATR-FTIR to retain the legibility of evidence since ATR-FTIR is known as non-destructive, fast, reliable, and precise instrumentation. Various modifications and developments to this technique have been published. Therefore, this work reviews the trend of analysis performed on samples of the document and evaluates the current approaches to the capacity of using ATR-FTIR on such samples. Remarks on the comparison studies are also included.

Discrimination and source correspondence of black gel inks using Raman spectroscopy and chemometric analysis with UMAP and PLS-DA

In the examination of forged documents, ink analysis plays an important role and the forensic scientist is required to opine on the origin of ink and colorants when the physical appearance is similar. Also required is to link the ink with its source as this has an important bearing in solving cases involving documents. In this study, we have tried to explore a relatively new type of writing instrument, the gel ink pen, which is commonly used by perpetrators of fraud. The favorable approach in ink analysis is the non-destructive technique such as Raman spectroscopy combined with chemometrics for objective and automated examinations. Most of the studies so far used unsupervised chemometrics for data exploration like PCA and HCA without any use of supervised methods for classification and source prediction of inks. In recent years, more complex unsupervised algorithms such as t-Distributed Stochastic Neighbor Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP) have emerged, which are frequently employed in big data scenarios. These strategies are also appropriate for the type of data we used in this study. Partial Least Square-Discriminant Analysis (PLS-DA) is a supervised classification technique commonly used to classify samples into known groups and predict the class of unknown samples. The performance of PLS-DA has been reported to be near perfect for a dataset of few classes, however, its applicability for large datasets remains to be explored. In this study, we report the application of PLS-DA for the classification of black gel ink samples (n ​= ​140) from 14 different brands. To demonstrate the applicability of PLS-DA in a forensic investigation involving unknown ink deposited on documents, we have tested 11 unknown samples to the trained PLS-DA model, and have achieved 91% correct classification rate. We also demonstrated misclassification due to large datasets can be mitigated by UMAP exploration and then applying PLS-DA to a reduced number of classes datasets. The procedure of using UMAP and PLS-DA may prove useful for unveiling the identity of black gel ink deposited on forged documents.

Written in ink: Elemental signatures in octopus ink successfully trace geographical origin

In recent years, validation of seafood authenticity and provenance has attracted the attention of authorities and consumers. Increasing levels of food fraud has raised awareness regarding seafood traceability, especially in highly valuable and highly consumed seafood products, such as the common octopus (Octopus vulgaris). Seafood traceability studies based on trace element fingerprinting generally focus on muscle tissues or carbonate structures whilst the ink fluid has been overlooked. Untargeted multi-element Total Reflection X-ray Fluorescence (TXRF) analysis of O. vulgaris ink successfully discriminated four collection areas [91.2 % and 84.1 % using Variable Importance in Projection Partial Least-Squares Discriminant Analysis (VIP-PLS-DA) and Linear Discriminant Analysis (LDA), respectively] along the mainland Portuguese coast (ca. 900 km coast in the Northeast Atlantic). Arsenic, Pb, Na, Sr and Rb were highlighted as elements with higher contributions for sample discrimination between the four considered capture areas. Regarding food safety, it is important to note that some ink samples Cu, Mn and Pb concentrations exceeded human consumption recommended values. Thus, the results show that untargeted TXRF spectroscopy analysis of O. vulgaris ink is a reliable tool for disentangling the geographical origin of the octopus, as well as to inform about the food safety of octopus ink.

Research on ink blot evaluation of aged paper before and after restoration

Abstract To evaluate the changes in the ink on paper subject to accelerated degradation before and after restoration treatment, an evaluation index describing changes to ink on paper documents before and after deacidification and enhancement by combining subjective and objective evaluations was established to improve the evaluation of the effect of deacidification and enhancement agent on the restoration of paper from the perspective of the ink thereon. According to the test indicators, test and control standard boards were designed and the paper for accelerated degradation was produced. In the experiment, 0.4 mol/L sodium carbonate solution, 6wt% styrene butadiene latex (SBR latex), sodium silicate, and polyamide polyamine epichlorohydrin (PAE) compound solution was applied to the accelerated degradation paper samples, respectively. After treatment, the quality indices such as color density, color difference, handwriting contrast and handwriting line width were measured. And observers were organized to make subjective evaluation on the accelerated degradation samples before and after the treatment. The results showed that the color density of magenta ink sample decreased by 10.61 % and the edges were blurred. The contrast and line width of handwriting after the treatment were decreased slightly. After treatment with 6 wt% SBR latex, the ink density of black increased the most (by 31.62 %) with no clear change in the handwriting contrast and line width. When using sodium silicate and PAE compound solution, the comprehensive effect on the text was much better. The results of subjective evaluation were consistent with the changes of objective indices.

Improving quality of smoked sardine fillets by soaking in cuttlefish ink

Cuttlefish ink, a by-product of food processing, is a promising source of natural compounds with antioxidant and antimicrobial activities and it can be used as a natural additive for sea food products. Therefore, this work aimed to extend the shelf life of smoked sardine by soaking in cuttlefish ink solution. No antibacterial activity of cuttlefish ink solution with different concentrations (1%, 2% and 3%) has been determined against Staphylococcus aureus, Listeria monocytogenes and Pseudomonas aeruginosa. DPPH radical scavenging activity for the ink samples ranged from 91% to 95% for the three ink solutions. Fresh fillets were steamed, smoked and soaked in the three ink solutions and then stored at 4 °C for 35 days. During storage, total viable counts, total volatile basic nitrogen values and peroxide values increased significantly only for control samples and those soaked with 1% of ink solution. Soaked samples showed the lowest amount of histamine when compared to the control one which may be related to a better controlled microbial proliferation. Ink solutions did not affect the whiteness of fillets, whereas the hardness increased significantly during the two first weeks of storage. Obtained results support using cuttlefish ink to lengthen smoked sardine shelf life.

Structural Analysis and Material Characterization of Silver Conductive Ink for Stretchable Electronics

Stretchable electronic systems have become more popular in various applications such as medical, fabric, flexible sensors for personalized health care, etc. There are two major parts of flexible and stretchable circuit boards that are substrate (a plastic material) and conductive ink (formulated polymer with conductive metal). According to electrical measurements, conductive ink plays a very important role in stretchable electronic equipment. The main objective of this paper is to develop a silver (Ag) based conductive ink and characterize its mechanical and electrical properties. Conductive ink is prepared by mixing an epoxy resin, cross –linking agent, additives (adhesion promoter), organic solvent, catalyst and silver flakes all together. ASTM D412 Type C dog bone shaped cutter is used to make three samples of conductive ink. The stress-strain analysis of conductive ink is carried out using universal testing machine (UTM). The conductivity is measured using two-point probe digital multi-meter. Also, the microstructural analysis, morphology and characterization are done by scanning electron microscopy (SEM). The images are taken after curing and tensile testing. The formulated ink possesses high conductivity and stretchability up to 137% strain. The achieved conductivity of the ink is 4.167×104S/m. The maximum stress before failure, yield stress, Young’s and tangent moduli are calculated as 1.195 MPa, 0.86 MPa, 5.72 MPa and 2.08 MPa, respectively. The SEM analysis indicates that the distribution of silver particles is uniform and in a good density throughout the sample.

Forensic analysis on printer inks via chemometrics

Printer inks are becoming necessary for utilization for wide range of purposes by society in current times with rapid development in technology and digital media area. Thus, forgery and counterfeiting becoming easier for the criminals. It is dangerous as some criminals will misused the technology by mean of addition and adulteration of parts of text or numbers on document as the inks and document can be made as an evidence in the trial court. Thus, the characterization and differentiation of the printed inks in the suspected documents (civil or criminal cases) may provide important information about the authenticity of the printer inks. The focus of this study to differentiate the chemical component of three different types of sample inks by incorporation of FTIR spectrophotometer with principal component analysis. The unique features of the ink samples were unmasked from the score plots of the principal component analysis. Thus, the graphical representation provided by the FTIR spectra with principal component analysis enabled the discrimination certain chemical in the printer inks.

Mahogany Sawdust Tannin as Ink Source

This study aimed to produce ink from Mahogany sawdust tannin. Specifically, it sought to determine the physical properties of ink using different amounts of glycerol as mordant; the physical properties of ink using different amounts of glycerol in terms of color, odor, and pH; the acceptability of the ink in terms of color, odor, and absorptivity; the best proportion of raw materials in the production of ink; and whether a significant difference exists in the physical properties of the inks in terms of pH. The study used the developmental and descriptive method that involved the production of ink, observation, and testing of the aforementioned properties, as well as a survey of the acceptability of the ink. One-way Analysis of Variance was used to determine whether significant difference exists in the pH of the inks produced using different amounts of glycerol. Findings of the study show that all three sample proportions were black, had a faint pleasant odor, and the pH values were consistent. The ink from Mahogany sawdust tannin was acceptable in terms of color, odor, and absorptivity. The best proportion of the raw materials in the production of ink is 10 milliliters tannin extract, 1 gram ferrous sulfate, 1 gram sodium chloride, 1 milliliter ethyl alcohol, and 3 milliliters glycerol. It has a darker color compared to the other two proportions containing 1 mL and 2 mL of glycerol, respectively. There is no significant difference in pH among the three ink samples containing different amounts of glycerol. The ink produced from Mahogany sawdust has been found very highly acceptable.

Development of black fungus-based 3D printed foods as dysphagia diet: Effect of gums incorporation

With the aging population trend, there is a great demand for dysphagia diet as the elderly suffering from dysphagia is increasing rapidly. 3D printing is capable of processing mashed and not attractive dysphagia diet into appetizing foods with appealing appearance. Black fungus (Auricularia auricula) illustrates many health-promotion effects, but its elastic texture and great chewing efforts making it unfeasible for the elderly. In this work, we studied the feasibility to develop 3D printed visually appealing texture modified black fungus-based food as potential dysphagia diet, with addition of gums (0.3%, 0.6%, 0.9%, w/w), i.e. k-carrageenan gum (KG), xanthan gum (XG) and arabic gum (AG). Results indicated that KG and XG addition significantly increased the mechanical strength (yield stress and elasticity), viscosity, hardness and gumminess of ink samples by reducing water mobility and facilitating hydrogen bond formation, while AG addition showed an opposite effect. International dysphagia diet standardization initiative (IDDSI) tests indicated that AG and KG containing sample failed the spoon tilt test within IDDSI framework, while XG containing sample could be classified as level 5-minced and moist dysphagia diet. 3D printed samples using control or AG containing ink illustrated poor self-supporting capability. KG containing ink was not easy for extrusion with defective points in printed samples. In contrast, XG-0.9% samples demonstrated high printing precision with great self-supporting capability and smooth surface texture. This work provides insights for the development of visually appealing dysphagia diet using 3D printing.

Comprehensive study of objects of judicial and technical examination of documents in solving issues regarding the establishment of their making

The article is devoted to the analysis of the essence of integrated research during the judicial and technical expertise to establish the prostitution of documents. The attention is drawn to the fact that the forensic examination with the establishment of the preparation of documents is the most difficult among other species of this kind of examinations and to be complex. The authors consider the peculiarities of this type of expertise and emphasizes that such examinations have difficulty in carrying out the use of special equipment and physicochemical research methods. The paths of determining the preparation of the paperwork are emphasized: determining the specific time of manufacture of each of the details with a further comparison of the results obtained among themselves; establishing conformity between the time of signature and handwritten records; the printing time of printing and text printing time, establish a chronological sequence of details in the document.
 It was concluded that the decision of the expert problem with establishing the prescription of the document requires the use of so-called "destructive methods". The main complexity of the examination of the process of making the preparation of the document is that when conducting any actions with a document (cutting, selection of ink samples), the document can be fully or partially destroyed. In this regard, expert institutions that take an obligation to carry out such examinations, pay attention to the ability to damage the document and in this connection declare a relevant request for permission to carry out such actions. Such permission should be in the document on the appointment of expertise or in the letter. Attention is drawn to the fact that not the provision of information about the time of receipt of the document may lead to the impossibility of determining the prescription of the document. After a long time and complex research process, the expert is forced to give a conclusion "is not possible."