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THE ATTIC : Disputed Documents	Date Added JAN 2004
At its simplest, document analysis is one of the oldest of the forensic sciences; as far back as classical Rome the made the provision for evidence of handwriting comparison to be given in court. Indeed, there were handwriting experts whose testimony was regarded with the same credibility as today's document analyst. Curiously, the English were very backward in accepting handwriting evidence, and it was only in the nineteenth century with the development of what were regarded as more 'reliable', scientific methods of identification that it became adopted. In the United States the debate really opened at the turn of the century when courts began to make individual rulings, and by 1913 Congress had enacted a statute which read, in part: 'In any proceeding before a court or judicial officer of the United States where the genuineness of the handwriting of any person may be involved, any admitted or proved handwriting of such person shall be competent evidence as a basis for comparison by witnesses, or by the jury, court, or officer conducting such proceeding, to prove or disprove genuineness.' Since then, document analysis procedures have kept pace with science, and their practitioners are seen as contributing to the wider issue of forensic investigation. For the purpose of this brief overview, a convenient definition of 'document' is something that contains information and is usually made of paper. In document examination the information contained occurs on two levels: 1. The superficial level: Where the document's information, or message, is expressed by such means as handwriting, typewriting, or printing; and 2. The hidden level: Where the less obvious information can be found - evidence of fraud or forgery for example. It is with the second level of inquiry that the document examiner is concerned. This information will be of vital importance first to the police investigators and subsequently, perhaps, in a court of law. Like other branches of the forensic sciences, document examination depends on identification and comparison.
The Love of Money
Apart from carrying sufficient funds to make small purchases, most people in the modern developed world have all but eliminated the need for currency. The transfer of money between individuals, between individuals and institutions and between institutions is now carried out by a wife range of transactions that transfer figures from one place to another. Cheques, credit and charge cards are today's main means of purchase, and few individuals do not rely on this means of transaction. The only means of indication normally required is a signature. Every time a cheque is written, a charge card used, the owner signs his name for comparison with the 'control' signature on his card. Not surprisingly the versatile forger has become responsible for frauds amounting to millions of dollars each and every year. The most common frauds are committed with cheques, closely followed by credit cards. The fundamental principles of detecting frauds in these cases is common to all document examination - a comparison of the suspect, or 'disputed' document, with a known specimen of a person's signature/handwriting. And for this reason, particular emphasis is placed on examination of handwriting.
Handwriting Analysis
An individual's handwriting depends for its character upon the interaction of brain, eye and hand. It is affected by a person's physical and emotional well being, the position in which he is writing, and circumstances which might control speed. So in fact a person may have several handwritings, several signatures (indeed, two identical signatures could look suspicious!). That said, there is, underlying these superficial deviations, an individual style which can be identified even though a person is trying to disguise his hand; the ways in which letters are started and ended for example, or the individual shapes such as whether or not the round letters like 'o' and 'a' are closed, the angle of the writing, its relationship to an imaginary straight line across the page, etc. The process of analysis and comparison is a long and painstaking one, and too complex to be encapsulated here. In the matter of signatures, there is a basic technique which will indicate whether or not it has been forged. Remember, no two signatures are exactly identical so it is useful for the analyst to have as many known examples of the genuine signature as possible for comparison - say, driving licence, marriage licence, etc.
Top-of-the-Letter Comparison
A tracing sheet is placed over the suspect signature (a photocopy should be used to avoid handling original evidence which may be required for fingerprint checks, etc.) and a small mark is made at the highest point of the letters above an imaginary baseline on which the signature sits. Each mark is then joined to the next, which will present a zig-zag line across the signature. The process is repeated for each of the known genuine signatures and the results compared.
Bottom-of-the-Letter Comparison
This time the tracing paper is marked with a dot at the bottom of each letter, and the results compared as above.
Spaces
The procedure is repeated for each of the signature spaces, both between words and, if there are any, between lines.
Slant Comparison
For this stage, the tracing paper is put over the suspect signature and an oblique line drawn through each of the letters that are above the base line. The lines are compared when this process has been repeated on the genuine signatures. Finally, the slants of the letters below the base line (the descenders) are plotted. Further distinctive similarities and difference of letters will be noted for the final detailed report, but this simple procedure will give an almost immediate response to the the fundamental question: Is the signature under consideration genuine or false?
Typing Comparisons
Over the past one hundred years the typewriter has undergone many changes as manufacturers have absorbed new technology and with the speed at which the miniaturisation of computers and word processors is proceeding, lap-top electronics could make the old manual typewriter a thing of the past. For the moment, though, there are sufficient numbers of 'traditional' typewriters in use - albeit most of them are at least electric, if not electric - for the acquired knowledge of typewriting analysis and comparison to remain valid.
Typeface
Although adjustments and refinements have been made over the years, the general design of what we know as the 'typewriter' style of letters has remained fairly standard - its most noticeable difference from printing type being that with a typewriter all the characters are the same width. Of course, each manufacturer will have small variations, and within a single manufacturer's range of typewriters there may be differences of face. Some of the most common alternatives are the numbers 3 (with either a flat or a curved top), 4 (with an open or closed triangle), the letters M and W (the centre point extending either the whole depth of the letter or only half-way), the cross bar on the t, etc. Less common typewriter faces are available without serifs (sans serif) or in script. Modern machines of a certain type print from a single moulded element - the familiar 'golf ball' or 'daisy wheel'. With these, it is possible to interchange the elements which are available in a wife range of typefaces, sizes and weights. The printers attached to computers and word processors are often so sophisticated that they are able to produce illustrations as well as a vast range of existing and custom-created typefaces. It is always useful to be able to identify the model of a typewriter responsible for 'writing' a particular document, as it will narrow the field when the original machine is being looked for. This information may also prove or disprove the supposed date of a typed document - for example, if it is a letter dated 27th July 1927, and the machine on which it was typed was not in production until 1937, then it is clearly very suspicious. Most forensic laboratories with an active documents department will have access to specimens of most makes of typewriter, and in Britain there is available a computer-based sorting method that can be used from terminals world-wide. Interpol (International Criminal Police Organisation) has a vast card-based system in which the type styles are classified according to letter spacing and key features of numerals and letters.
Individual Comparisons
The most important evidence that can be deduced from a typewritten document, in the forensic sense, is which individual machine it was written on. This information may prove vital in cases where, for example, a kidnap ransom note or extortion letter has been typed. In one of the most celebrated cases in American legal history, two young men, Nathan Leopold and Richard Loeb, the sons of wealthy Chicago families, kidnapped and murdered a fellow student just to see whether it was possible to commit the perfect murder. As it turned out it was a most imperfect murder, for not only had Nathan Leopold left his spectacles on the ground where they dumped the body of Bobby Franks, but the ransom note sent to Bobby's millionaire father was typed on Leopold's typewriter. The killers were tried and convicted in 1924, and only an impassioned plea by the famous defence attorney Clarence Darrow saved them from the death penalty. Although typewriters leaving the factory will to some degree carry minor imperfections, such as in the casting of letters, or the fine alignment, by far the greater number of identifying 'fingerprints' will be imposed on a machine during its working life. The letters can become chipped and unevenly worn, alignments can be disturbed by frequent or heavy use causing a slant backwards or forwards, or at an angle, or it may produce an uneven print image. The 'shift' key could become worn or damaged so that capital letters no longer align with the lower case. Electric machines are prone to similar distinctive wear and tear, and in addition the pressure adjustments for some of the letters may become faulty and the characters consistently print more heavily or lightly. Despite the more compact design, type balls or 'golf balls', are liable to have letters chip and the mechanism which rotates the ball can become slightly misaligned producing a characteristic unevenness of pressure or of alignment. The same is true of 'daisy wheels'. The method of making a comparison is similar to comparing handwriting. Typescript presented as evidence it matched against a control sample typed on the suspect machine and similarities (or differences) noted. Where much finer comparison is required - for example, in the case of a new machine with no wear and tear features - it is possible to check the vertical and horizontal alignment of the letters with a sheet of clear plastic specially calibrated with a grid to match the line and letter spacing of a particular model of typewriter. When the grid is placed over a sample of typewriting, each letter should, in theory, be centrally placed in a small box. Very slight misalignments can thereby be checked and compared.
The Comparison Projector
This apparatus works, in effect, like a comparison microscope. Two documents are projected on to a screen (the degree of enlargement is largely a matter of choice) and can either be superimposed so that a check can be made for similarities and differences, or the document can be flashed alternatively so that it can be viewed in the same frame in quick succession. Obvious damage to the letters adequately identified with the naked eye will simply appear larger, but it is possible to locate and compare quite small imperfections and fine misalignments when the images are enlarged.
Carbon Papers and Ribbon
Mention must be made of the almost Sherlockian ruses employed to re-create a missing document. If carbon paper has been used to make a copy, the reversed image of the letter typed through it can be clearly seen and, viewed obliquely to the light in a mirror, read. To give a clear, sharp image many modern typewriters make a one-use carbon ribbon. The plastic film carrier strip is coated with carbon and as each key is struck it transfers the character on to the paper before moving on. As each section of ribbon is used only once it is possible by unwinding it and writing down all characters that have been punched out of the carbon, to re-create the document letter by letter.
Indented Writing
If one sheet of paper is directly under another being written on it will pick up an impression of the writing. Legibility will depend on the thickness of the paper, whether the sheets were on a hard or soft surface, and the degree of pressure by the writer. The significance of this effect is obvious in cases where an indented sheet is found which can be matched with a threatening letter, an attempt at blackmail or a ransom note. Another occasion on which indented impressions can disclose vital information to the document examiners is when pages have been torn from a book - a diary, say, or an accounts book.
Revealing Impressions
The simplest method of 'reading' impressions is to hold the sheet of paper in question at an oblique angle to a light source, which produces shadows in the depressions making them clearer. The document can be photographed in this light to create a permanent record.
Electrostatic Detection Apparatus (ESDA)
This machine, manufacture by the Foster and Freeman company of Worcestershire, England, is based on the curious and inexplicable phenomenon that impressions on a sheet of paper alter its dielectric properties. If an electrical current is applied to the surface, a different potential is created at the impressions but not on the surrounding area. The apparatus comprises a flat bed made from the porous metal sintered bronze, below which is a vacuum suction, and above which runs a reel of transparent plastic called Mylar. A separate moveable box called a corona discharge unit has a thin wire stretched along its length capable of being charged to about eight kilovolts. The document is placed on the electrically earthed bed of the apparatus, covered with Mylar, and the resulting 'sandwich' held to the bed by vacuum suction. The corona discharge unit is switched on and passed over the Mylar several times, imparting an electrostatic charge. The bed of the ESDA is now tilted at an angle and a mixture of photocopier toner and fine glass beads is sprinkled over the surface. The greater potential created at the site of the impressions attract the black toner. This enables the impressed images to be read with greater or lesser ease depending upon the depth of the indentation. ESDA has been used with success in cases where impressions were not visible to the eye. One caution is that although the technique will still work several years after the first writing, treatment with any solvent will negate the effect. The test must consequently be carried out before any treatment to reveal latent fingerprints. A method similar in principle to ESDA is the Electrostatic Mat used to enhance otherwise weak and incomplete Shoe Prints.
Charred Documents
Whether the condition was caused by accident or malicious intent, one of the most difficult tasks for the document laboratory is handling charred paper. Often, however, with sufficient care and specialised treatment, the most unpromising debris can be 'read'. The care must start at the scene of the 'crime' - which may be a fire, or simply documents burned as part of a connected crime - embezzlement perhaps. After photographing at the scene, the charred remains must be handled with great care. They will frequently be fragile, twisted and warped, and can crumble with any attempt at flattening. Successful stablisation of charred paper has been achieved by spraying a three per cent solution of polyvinyl acetate in acetone which allows the sheet to be gently flattened and hand-delivered to the laboratory in a cotton-wool lined box.
Paper
The bulk of the world's paper is now made from wood-pulp, though special papers still use linen and cotton and various vegetable fibres. There are special additives to security papers (used, for example, in the printing of currency) which make forgeries easier to detect. A world price rise in the natural raw materials of paper, coupled with greater ecological awareness, has resulted in the development of a number of synthetic fibres for paper production. Fibres, whether natural or synthetic, are frequently 'filled' with a fine chalk material to give the paper greater opacity, less absorbency and more bulk. For fine colour printing the 'whiteness' can be enhanced by the addition of optical brighteners such as fluorocarbons. In addition, the surface of the paper may be treated by heat rolling, sizing, starching, or with synthetic resins. All these separate distinctive products and processes combine to endow paper with, if not a 'fingerprint', then at least a set of reference standards to help in comparison. This analysis of 'type' will be the essential first step in deciding whether a document is genuine or whether it is a forgery. One would not, after all, expect to find a first folio of Shakespeare printed on synthetic paper, any more than one would trust one of the Bard's letters written with ball-point ink. Microscopic examination of the paper fibres will reveal information about the type of tree from which it was pulped and, as paper frequently has more than one type of wood in its production, the area of similarities narrows.
Watermarks
Watermark patterns are moulded into the continuous roll of paper (or single sheet) during manufacture, and for centuries have identified the mill from which the paper originates as well as its type, or 'brand'. Watermarks change over the years, and even within the same type of paper from the same mill some type of rudimentary dating can be achieved by comparison with reference collections. Because it is put into the paper at an integral stage in its manufacture, the watermark is impossible to reproduce exactly. Attempts to rub through a stencil to remove the top layer of fibres are apparent even under low magnification, and fake marks 'printed' in oil from a woodcut can be distinguished from the original because the edges of the design are sharper. One method which can mislead the unwary is the technique of pressing damp paper between two plates, one bearing the raised design of the watermark. This has the effect of compressing the paper fibres beneath the area of the design giving a good likeness of an original. However, under magnification it can be seen as compressed paper, whereas the original mark is there because there are fewer fibres where the mark is.
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