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| ORIGINAL ARTICLE |
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| Year : 2017 | Volume
: 3
| Issue : 1 | Page : 31-37 |
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Influence of Software on the Features of Laser-printed Characters
Yuanli Han1, Xingzhou Han2
1 Collaborative Innovation Center of Judicial Civilization; Department of Forensic Science, Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education, China
2 QD Examination Division, Institute of Forensic Science, Ministry of Public Security, China
| Date of Web Publication | 31-Mar-2017 |
Correspondence Address:
Yuanli Han
Collaborative Innovation Center of Judicial Civilization; Key Laboratory of Evidence Science, China University of Political Science and Law, Ministry of Education
China
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jfsm.jfsm_13_17
Verifying the authenticity or otherwise of printed documents is one of the most important aspects of questioned document examination and plays a vital role in the field of forensic science. In recent years, continued developments in the quality of impression combined with ever-cheaper toner printers have allowed this technology to spread. It is now used in an increasing number of homes for all types of documents, including for criminal aims. Here, the factors that influence the printed features in text files are studied in relation to the operating system and the word processing software. The Net Application report in October 2014 showed that the market shares of Windows 7 and Windows XP were 53.05% and 17.18%, respectively. The Forrester report in October 2013 showed that the market share of Microsoft Office was more than 85%, the top three word processors being Microsoft Word 2003, 2007, and 2010. In this study, Windows XP (shortened to XP), Windows 7 (shortened to Win7), Microsoft Word 2003/2007/2010, WPS Office 2013, and the PDF format are chosen as the most common operating systems and word processing software. WPS Office was developed by the Chinese company Kingsoft Co., Ltd. and is widely used in China. A particular text file was designed and edited and was printed on a laser printer. The features of the printed characters were captured using an Anyty 3R digital microscope, Printer Expert, and X-printer devices. Coincidence comparison and outline feature extraction were used to evaluate the differences. It is shown that XP and Win7 have no effect on the printed features of text files. However, the printed features do depend to a certain extent on the word-processing software, with the PDF format having the greatest influence. Keywords: Laser printing, office software, operating system, printing features, questioned document
How to cite this article:
Han Y, Han X. Influence of Software on the Features of Laser-printed Characters. J Forensic Sci Med 2017;3:31-7 |
| Introduction | |  |
Verifying the authenticity or otherwise of printed documents is one of the most important aspects of questioned document (QD) examination and plays a vital role in the field of forensic science. Laser printing, which became popular in the mid-1990s, is based on laser scanning phototypesetting technology that was developed in the late 1980s. Their superior print quality, working efficiency, print load, and printing stability have made laser printers the mainstays of modern offices. Their universality also makes them the main tool used to counterfeit or otherwise alter documents. The main types of such cases in China involve national public security (e.g., reactionary leaflets), criminal cases (e.g., counterfeit money, threats, defamation), economic fraud (e.g., fake contracts), and civil disputes (e.g., contracts, IOUs, receipts).[1]
In practical cases, identifying whether multipage documents were printed on the same printer is very common, and there are well-established methods [2] for doing so. However, it is often the case that the forensic examiner is presented with the QD and the suspect printer, but not with the computer that was connected to the printer. If the suspect printer is connected to a different computer that is using different word processing software (either in relation to the make or the version), the question then arises as to whether the printing features remain consistent when the QD is reprinted. The aim of this study is to compare the printing features of different operating systems and office software. The results are expected to inform best practices for printing samples for forensic examination.
| Materials And Methods | | |
Design scheme
T1: Study the similarities and differences between characters printed under the same operating system (Windows XP) but from different word processing systems [Figure 1]. | Figure 1: T1 experimental roadmap: Characters printed under the same operating system (Windows XP) but from different word processing systems
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T2: Study the similarities and differences between characters printed under the same operating system (Windows 7) but from different word processing systems [Figure 2]. | Figure 2: T2 experimental roadmap: Characters printed under the same operating system (Windows 7) but from different word-processing systems
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T3: Study the similarities and differences between characters printed from the same word-processing system (Microsoft Word 2003) but under different operating systems [Figure 3]. | Figure 3: T3 experimental roadmap: Characters printed from the same word processing system (Microsoft Word 2003) but under different operating systems
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Materials
Equipment: DV4 stereo microscope, Anyty 3R digital microscope, Printer Expert, X-printer.
Laser printer: Canon LBP 2900 monochrome laser printer.
Paper: UPM Classic Jetset 70-g/m 2 pure-white A4 copy paper.
Text: More than 50 printed documents containing the 10 most-frequent words and punctuation symbols, including the characters “, (comma)”, “₀,(period)”, “1”, “ (de)”, “ (nian)”, “ (yue)”, “ (ri)”, “ (wan)”, “ (yuan)”, and “ (qian).
Methods
Source identification of laser-printed documents now mainly relies on trace features, for example the trace on the OPC. The morphological features of printed pictures and characters is also very important, especially to the continuous printing examination. The most commonly used and basic method is comparison, which can be facilitated by Printer Expert, X-printer, Photoshop, or other equipment or software. This paper used coincidence comparison and outline feature extraction to evaluate the character printing features,[3] as shown in [Figure 4]. | Figure 4: Examination methods (a) Coincidence comparison (b) Outline feature extraction
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| Results and Discussion | | |
Stability of printing features under the same operating system and from the same word-processing software
Because of space limitations, we assess the printing stability for only two combinations of operating system and word processing software. A file was prepared that contained the characters “ ” and “₀”. It was printed three times under XP (Microsoft Windows XP Professional, version 2002, Service Pack 3) from Microsoft Word versions 2003 and 2007. The results are shown in [Table 1] and [Table 2], respectively. | Table 1: Stability of features printed under XP from Microsoft Word 2003
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 | Table 2: Stability of features printed under XP from Microsoft Word 2007
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As can be seen from the threefold character prints in [Table 1] and [Table 2], there were no significant differences in the edges of the character strokes, the toner distribution pattern, or the stroke forms for characters printed from Microsoft Word 2003/2007. In other words, the printing characteristic is very stable for two different characters. Thus, we conclude that the features of the printed characters remain stable under the same operating system from Microsoft Word.
Comparison of printing features under the same operating system (XP) but from different software
Two variants of Microsoft Windows XP Professional, version 2002 were tested: Service Pack 2 (XP-1) and Service Pack 3 (XP-2). Choosing “,” “1” and “ ” as the sample characters, coincidence comparisons were conducted between printing from Microsoft Word 2003/2007/2010, WPS Office 2013, and Adobe Acrobat 7.0 Professional. The results are shown in [Table 3],[Table 4],[Table 5].
It can be seen in [Table 3],[Table 4],[Table 5] that, under the same XP operating system, there are no significant differences between Microsoft Word 2003/2007/2010 and WPS 2013 in relation to the edges of the character strokes, the toner distribution pattern, or the stroke forms. However, there are considerable differences between the features printed in the PDF format and those printed from Word/WPS. Using the same office software, the features printed under XP-1 and XP-2 have not obvious and steady differences.
Comparison of printing features under the same operating system (Windows 7) but from different software
Two variants of Microsoft Windows 7 were tested: The professional edition (Win7-1) and the home edition (Win7-2). Choosing “,” “1” and “ ” as the sample characters, coincidence comparisons were conducted between printing from Microsoft Word 2003/2007/2010, WPS 2013, and PDF. The results are shown in [Table 6],[Table 7],[Table 8].
It can be seen in [Table 6],[Table 7],[Table 8] that, under the same Windows 7 operating system, there are no significant differences between Microsoft Word 2003/2007/2010 and WPS 2013 in relation to the edges of the character strokes, the toner distribution pattern, or the stroke forms. However, there are considerable differences between the features printed in the PDF format and those printed from Word/WPS. Using the same office software, the features printed under Win7-1 and Win7-2 have not obvious and steady differences.
Comparison of features printed under XP and Windows 7 from the same software
[Table 9] shows the results of printing the characters “ ” and “,” from Microsoft Word 2003 under XP-1 and Win7-1 as an example. There are no obvious differences between the various printed features.
| Conclusions | | |
It was shown that the XP and Windows 7 operating systems have no effect on the printed features. However, different word processing software does show certain differences. The PDF format shows appreciable differences in printed features compared with those produced from Microsoft Word and WPS Office. The overall results are summarized in [Table 10]. | Table 10: Summary of factors affecting the features of printed characters
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Printing features determine the conclusions of identification, and examiners depend mainly on comparisons of these features to give an expert opinion. There are many types of printing features, such as trace features, fault features, pollution features, microscopic toner features, and dot features. The test results presented here have demonstrated clearly that examiners should pay more attention to factors that can affect printing features. When identifying printed characters, the same printer, operating system, and word processing software is required. The results also suggest that various comparison tests should be designed (e.g., pictures) to facilitate more applicable and accurate forensic deductions.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Yuwen J, Mingli Z. Questioned Document Examination. 1 st ed. Beijing: Chinese People's Public Security University Press; 2001.  |
| 2. | Fritz T, Herry F. 16 th International Forensic Science Symposium. Lyon: Interpol; 2010. p. 354. |
| 3. | Jiantong H. Questioned Document Examination. 1 st ed. Beijing: Chinese People's Public Security University Press; 2012. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]
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