FORENSIC SCIENCE PAPER No.8: Questioned Document MODULE No
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SUBJECT FORENSIC SCIENCE Paper No. and Title PAPER No. 8: Questioned Document Module No. and Title MODULE No. 29: Scanned Documents and Facsimile Machine Module Tag FSC_P8_M29 FORENSIC SCIENCE PAPER No.8: Questioned Document MODULE No. 29: Scanned Documents & Facsimile Machines TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction 3. Computer- Generated Documents and the Forensic Examiner 4. Examination Procedure 5. Description and Histories of the Technologies 6. Identification Features of the Printing Processes 7. Summary FORENSIC SCIENCE PAPER No.8: Questioned Document MODULE No. 29: Scanned Documents & Facsimile Machines 1. Learning Outcomes After studying this module, you shall be able to- Know about various Technology of Printers Learn about the history of various Technology Identify the printer technology with the help of identifying features 2. Introduction One of the most extraordinary skills that we as human beings possess is written communication. Unlike a conversation, our written words allow us to transmit ideas not only over distance, but also over time. It would seem that the urge to make a record of our lives is as old as man himself. Even before there was writing, ochre and charcoal drawings in caves show our ancestors recording important daily events, such as a particularly successful bison hunt — creating, perhaps, the earliest form of textbook or, then again, maybe just bragging rights. Our progression from pictographs to graphical user interface has taken place over a remarkably short time. At no time in man’s history, however, have the documents we make and print gone through more dramatic technological changes than in the past 30 years. The ephemeral world of thought has been transformed into something tangible using the equally ephemeral electric charges held in a silicon memory register. Our ancestors would have understood why we want to tell a story, but they could never have imagined how. To quote the famous science fiction writer Arthur C. Clarke, “Any sufficiently advanced technology is indistinguishable from magic.” The history of recording our thoughts in printed form is also the story of mankind’s changing technology. At almost every major technological advance there has been a corresponding change in the way we record and store our ideas. Certainly some of the earliest attempts at industrial chemistry and technological innovation came from the efforts to make better inks and dyes. The adaptation of moveable, recast able, hot metal type in the late 16th century helped to spread literacy across Europe. During the 17th and 18th centuries metallurgists gradually learned how to increase the strength of iron and steel. The typeface designers quickly took advantage of the harder metals by creating new type fonts with finer detailing and smaller sizes. Because of the greater readability of these newly created alphabets, more letters could be strung together on a page, thus saving paper and ink costs for the printers and publishers. As printing costs were reduced, the distribution of the printed word on pamphlets, flyers, and, of course, books began to spread among the population. The information technology of the day continued to move in lockstep with general technological innovation. FORENSIC SCIENCE PAPER No.8: Questioned Document MODULE No. 29: Scanned Documents & Facsimile Machines 3. Computer- Generated Documents and the Forensic Examiner In the late 1960s it was considered mandatory in the field of questioned document examination to read Ordway Hilton’s, Dr. Phillip Bouffard’s, and Dr. David Crown’s treatises on the examination of typewritten documents. At that time the business community was just upgrading their typewriters from manual and electric single-font machines to the new IBM Selectric typewriters with interchangeable type elements. For the first time, the identification of a typewritten text required the identification of a typing system, rather than just the typewriter. Since defects could occur on the type element or in the typewriter itself, it became necessary to contend with the fact that an element could be moved from machine to machine or a machine could use multiple elements. It was, therefore, the combination of typewriter and interchangeable element that was identified as a system. In the space of just 40 years we have gone from the Selectric — arguably the most technologically advanced typewriter of its day — to the computer age. A document creation system that had just two parts in 1961 (typewriter and element) can now have multiple components — some based in software and some in hardware. The modern Forensic Document Examiner must be aware of such things as the operating system, the word processing program, the version of the word processing program, the digital font and version of the font file, the printer driver and its release date as well as the connection to the printer (standalone or networked). All can have an impact on the appearance of the printed text, as can the many variables associated with the printer itself. Make no mistake about it — this is a complex area that requires some knowledge of typography, digital fonts, computer systems, and software. All of these topics could (and have) filled their own textbooks. This chapter provides a boiled-down version of what is believed to be the most important information for those engaged in the forensic examination of computer-generated documents. 4. Examination Procedure An examination will often be conducted to help answer the questions that are at issue in the case. Some of these questions are likely to include: 1. Is the document an original or copy? 2. Can the printing technology be identified? Dated? 3. Has more than one technology been used to prepare the document (letterhead printed on a lithographic press — the variable data printed with dry toner)? FORENSIC SCIENCE PAPER No.8: Questioned Document MODULE No. 29: Scanned Documents & Facsimile Machines 4. In a multi-page document, is there evidence that one or more pages are prepared differently than the others? 5. Is there any evidence that text has been altered or added to the document? 6. Are there any obvious (gross) defects in the printing that might lead to the machine being individualized? In general, the well-established principle that documents should be thoroughly scrutinized on both sides, corner to corner, is just as valid for modern, computer-generated documents as it has been since the dawn of forensic document examination. 5. Description and Histories of the Technologies 1. High-Speed Mainframe Line Printers: Drum and Chain Print heads This class of printer was first developed in the early 1950s for use with the huge mainframe computers that were just beginning to come online. There were two main types of line printers: drum printers and chain printers. The IBM model 716 that sold from May 1952 through July 1969 was the most widely distributed of the drum printers. In this class of printer, the print mechanism consisted of 120 type wheels (disks) arranged together as a cylinder (drum) behind the ribbon. These wheels spun into the strike position and printed an entire line at a time. At full speed these printers could produce about 150 lines per minute. The model 716 print wheels had 26 (all capital) letters, the numerals 0 to 9, and nine special characters, such as the dollar symbol, period, and slash. The most widely used line printer, however, was the IBM model 1403 introduced in October 1959 and discontinued in 1971.This printer utilized a rotating chain with characters affixed to one side. There were 240 characters affixed to the chain, usually arranged in 5 groups of the same 48 characters. The impact mechanism consisted of 132 hammers arranged much like the hammers over the strings in a piano. The hammers were used to strike the back of the paper against an inked ribbon and the spinning chain at exactly the right moment to impress the characters onto the page. An examination of the text should show the typical pattern made by a metal character striking a fabric ribbon. FORENSIC SCIENCE PAPER No.8: Questioned Document MODULE No. 29: Scanned Documents & Facsimile Machines The 1403 was typically fed 11×14-inch fanfold (green-bar) paper and could print up to 1400 132-column lines per minute. All of the chains that were used by the 1403 contained monospaced characters. At some point in time during the 1960s, however, special chains became available that utilized a Courier font in a full set of upper- and lowercase letters, numbers, and symbols. These special chains could be ordered with as many as 120 different typographic characters arranged on the chain in two groups. These special chains and the 1403 printer became a particularly popular way for companies to produce their own technical/policy manuals. As of 2004, the Lexmark Division of IBM was still selling nylon ribbons for 1403 printers. 2. Dot Matrix Printers Dot matrix printers are technically described as impact matrix printers. This distinguishes them from non-impact matrix printers such as inkjet, thermal print head, and even laser — all of which create text and images as a series of closely spaced dots. The earliest development work on wire printers appears to be that of Reynold B. Johnson at IBM in 1949. By the mid- 1950s both Burroughs and IBM had developed high-speed wire printers for use with mainframe computers. These machines turned out to be highly unreliable and were never a commercial success. In 1968 Seiko Electronics manufactured a small dot matrix print head. This unit was used to print out hard copies of timed athletic events recorded by Seiko’s electronic timers at the 1972 Olympic Games in Tokyo. This small printer was known as the EP-101. Ten years later, in 1978, EPSON (SON of Electronic Printer) used the EP-101 dot matrix technology to market the first (under $2000) consumer dot matrix printer — the EPSON TX-80.