Handwriting can be described as the formation of letters, characters or symbols, using a writing implement, according to a recognizable pattern which is designed to communicate with another person. The issue of who wrote a particular piece of handwriting can be central to many legal proceedings. Accepted ways to prove handwriting include admission by the writer or the testimony of a person who witnessed the writing. If the writer is uncooperative or not available, and there are no apparent witnesses, or the writing is otherwise in dispute, then there is a need to resort to other means of identification. There are two other means acceptable by the courts. The first is to call a person acquainted with the writer’s handwriting; the second, and more reliable, is to employ the services of a forensic document examiner to undertake a comparative examination of the writing in question with known specimen handwriting of the suspected writer of the questioned material. A document examiner may be asked to examine such diverse documents as anonymous letters, writings and/or signatures on cheques, credit cards and vouchers, wills, mortgages, other legal documents, medical records and diaries. It should be noted that, although documents generally consist of writing on paper, the forensic document examiner can be called upon to examine writings on other less conventional documents such as blackboards, whiteboards, pieces of pasta, body parts, fence posts and graffiti on buildings, walls, windows etc.
Writing is taught from a model system. The act of continuously repeating a written character fixes the form of that character in the mind of the writer, normally during childhood, until the production of this form becomes ‘automatic’. From the moment people start learning to write, they introduce deviations from the model writing system taught. The extent of these deviations increases as the writing style becomes more personalized, resulting in a style which is the product of many factors including the model system, artistic ability, muscular control, nature of employment, frequency of writing and exposure to the writings of others. This results in an individual writing style, the development of which occurs throughout the childhood and adolescent years, and often beyond (Fig. 1).
A similar evolution can be seen in the development of a person’s signature with the individual practicing a certain style which changes over time under the influence of the factors described above, until an often quite individualized pictorial representation of the person’s name is formed.
Document examiners refer to writing characteristics attributable to a model system as being ‘class’ or ‘style’ characteristics. Different styles of writing are taught in different countries and sometimes regions, which accounts for some of the variability in handwriting styles. The styles taught also change over time. For example, in Australia today it is unusual to be taught the elaborate cursive style of writing which was once commonly taught. A number of terms are used by document examiners for characters found infrequently in the general population including ‘unusual’, ‘personal’ or possibly ‘individual’ characteristics. The term ‘individual’ characteristic is somewhat misleading if applied to one letter form, since one letter form even if very unusual is not sufficient to individualize, or identify, the writer. In order to distinguish the writing of any one person, the handwriting expert builds a background knowledge over time, from examination of the writings of many different people, of what can be considered common or unusualfeatures of handwriting and how handwriting can change under different circumstances. If sufficient handwriting is present, it is the combination of rare and common features which serves to identify a particular writer.
Figure 1 Ten people’s writing of the place name ‘Queanbeyan’, illustrating the differences and occasional similarities which arise in the writings of different people.
Although we use the terms forensic document examiner and handwriting expert interchangeably for the purposes of this article, it should be noted that the term ‘handwriting expert’ is sometimes used by those who seek to determine a person’s psycholo-gicalcharacteristics from their handwriting (graphologists). Caution should be taken when engaging the services of a ‘handwriting expert’ to ensure that the person engaged is fully trained and qualified in the field of forensic document examination. Although the bulk of the work of most forensic document examiners focuses on the scientific comparative examination of handwriting and signatures, there are document examiners who almost exclusively examine aspects of documents other than handwriting.
When a particular piece of handwriting is called into question, the handwriting expert will examine the writing in question visually, with the aid of hand held magnifiers and with a microscope. Features such as the details of construction of individual letters and letter combinations, comparative height and size relationships of particular letters and letter combinations, alignment of letters and words, slope, speed of writing, angularity, pressure, shading, diacritics and layout are considered.
Constructional details such as line direction and sequences of separate strokes can often be determined from microscopic examination. Evidence of the sequence of separate strokes can sometimes be obtained by the direction of any small terminating and commencing strokes between separate parts of a character, called spurs or ticks, or faint connections between these parts, showing the direction of pen traveljust before a pen lift, or just after the pen has contacted the paper following a pen lift. Usually, examination of several examples of each letter are required to make such a determination. Ball-point pen striations can also be used to determine line directions as such striations run from the inside to the outside of a curved stroke (Fig. 2). The striation pattern present at the conclusion of a stroke, may be retained on the ball of the pen and transferred to the beginning of the next stroke. This ‘memory effect’ can be used to determine the sequence of strokes. Other characteristics of the ball-point pen stroke that allow determination of direction of stroke include ‘gooping’ (an extra heavy deposit of ink) following a curve and dried or reduced ink starts at the beginning of lines. For this reason, it is strongly recommended that at least some of any requested set of specimen handwriting is written with a ball-point pen. Higher power microscopic ( x 30 or more) examination can also sometimes be used to determine line direction of ballpoint pen writing, and almost always for pencil writing. This can be determined from the build up of ink or graphite predominantly on the ‘upstream’ side of the paper fibers which faced the approaching writing tip.
Figure 2 Ball-point pen writings showing (A) striations and (B) reduced ink start. Arrows indicate direction of pen movement.
The known writing of the person suspected of writing the questioned document is examined in a manner similar to that employed with respect to the questioned document. Specimen handwriting needs to be comparable in style with the questioned handwriting. For example, questioned upper case block printing should be compared with specimen upper case block printing. It is also preferable to examine specimen writing on forms of a similar printed layout. Once suitable specimen handwriting is obtained, an initialcomparison is made between the known writing samples to ascertain if they can reasonably be taken to have been written by the one person; it can happen that documents which are said to bear the known writing of one person may include (at times unwittingly) the writing of other persons. This is a particular consideration when using diaries, address books or other documents where many persons may have had access to and written on the document. From the examination of specimen writing, the expert assesses how the writing of this particular individual varies within itself.
Once the requirements for suitable specimen handwriting are met, the questioned and specimen handwritings are compared with each other, and an assessment made of similarities and differences between the two writings. A character in the questioned writing is considered to be similar if it, or its range of variation, falls within the range of variation for this character in the specimen handwriting. If the character or its range of variation in the questioned writing falls outside the range of variation seen in the specimen handwriting (for example there are differences in form (shape) or in direction, number or sequence of strokes), then this is considered to be a difference. Some differences are regarded as more significant than others; for example, the repeated appearance of a different sequence or direction of strokes for a naturally written block capital letter (Fig. 3) or numeralmay be regarded as a more funda-mentaldifference than a shape difference of a lowercase cursive letter. If significant differences are found, this usually results in a conclusion that the two writings are unlikely to have been written by the same person or, alternatively, there is nothing to link the questioned and specimen writings as being by one person. Although definite negative conclusions are sometimes justified, they should be used sparingly and in specialcircumstances. This is because of the possibility which should be considered, although remote, of a person having two distinct handwriting styles. With similarities also, some are more significant than others. The significance is greater if it involves a handwriting feature found more rarely in the appropriate general population. This is usually assessed subjectively, based on the experience of the examiner in observing handwriting features in very many writers. The keeping of handwriting reference collections, and using such references to determine the rarity or otherwise of a particular feature, is becoming more prevalent and can provide some statistical backing for the results of handwriting comparisons.
Finally the examiner, before arriving at a finding, assesses the results of the comparison process in terms of similarities and/or differences in all comparable features of the handwriting and their significance. If no significant differences are found, the examiner assesses the likelihood that all of the similarities could have occurred by chance in the writings of two people, or alternatively could have originated in one person simulating the handwriting of another without leaving any evidence (see below) of the simulation process. These are usually assessed as subjective probabilities, based on the premise (from the probability multiplication law for independent events) that the probability of very many similar handwriting features, not necessarily individually rare, occurring in combination in the writings of two people is considered extremely small or negligible. Where the probability of a chance match in the writings of two people and the probability that another person has successfully simulated the writing style of the writer of the specimens are both considered negligibly small, the document examiner reaches an unqualified conclusion that the writer of the specimens wrote the questioned entry. Such a conclusion may on occasion be reached even where some apparent differences are found provided the document examiner is satisfied that these apparent differences are due to disguise, accidental formation or the use of an alternative letter form. Where the writer has made a correction or an accidental stroke caused, for example, by jolting of the pen, the character formed may vary from other examples of that character within the body of the text.
Figure 3 Two forms of the capital letter ‘E’ showing different sequences of strokes indicated by numbers.
On the other hand the document examiner may reach a conclusion expressed in terms of some degree of probability if doubts arise from:
1. the paucity of questioned or known writings;
2. the inherent quality of the document;
3. the disguised nature of the questioned or known writing;
4. the lack of contemporaneity between the questioned and known writings;
5. the lack of individuality in the writing; or
6. any other reason.
Such qualified findings may nevertheless be of assistance to investigators, lawyers and to courts on many occasions. It should be noted that these are subjective, not mathematically determined, probabilities and actually refer to the document examiner’s perceived probability of being correct in pointing to the writer of the specimens as being the writer of the questioned material.
There is no fixed amount of writing required for a definite handwriting conclusion, or other level of certainty. This is because the overall unusualness of the combination of features which makes up a person’s handwriting varies from person to person. Together, these character forms and other handwriting features make a person’s writing in most cases unique and identifiable. Where a person’s writing does not vary much from the modelsystem taught, considerably more questioned and specimen writing is needed in order to reach a conclusion as to whether this person wrote the questioned writing. Conversely, a highly individualistic writing can be identified with less questioned and specimen writing.
Occasionally, because of extreme limiting factors such as severe distortion of the questioned writing, the small amount of writing bearing only common features or inadequate specimens, the document examiner is unable to reach any useful conclusion and expresses the result as inconclusive.
In the case of a signature examination the examiner follows similar steps to those used for the handwriting comparison, firstly determining that the specimen signatures provided can be taken to be the signatures of one person, then comparing the specimen signatures with each of the questioned signatures in macroscopic and microscopic detail. It should not be assumed that in the case of multiple questioned signatures in one name that all of the questioned signatures have been written by the one person. Whereas handwriting comparisons usually require a reasonable amount of questioned handwriting, it is often possible to reach a definite conclusion that a highly personalized signature is genuine (Fig. 4) with much less questioned material. This is because the likelihood of a chance ‘match’ occurring between an idiosyncratic signature and the handwriting of another person writing this signature style without knowledge of the genuine signature is significantly reduced.
Figure 4 Varying degrees of personalization in a range of signatures.
For most, but not all signature cases, which involve the comparison of a set of specimen signatures with generally pictorially similar questioned signature(s), the main issue is whether the questioned signature was written by the writer of the specimens, or whether the signature was written as a simulation of the style of the genuine signature. It is not possible to determine by handwriting/signature comparison methods who wrote a completely simulated signature (or handwriting). In such a simulation the normal handwriting features are distorted by the simulation process. In less complete simulations there may be evidence of the writer’s naturalhandwriting characteristics. For most handwriting comparison cases, the main issue for generally similar writings is whether the writer of the specimens wrote the questioned writing, or whether a chance match has occurred in the writing of two people. It should be stressed that this does not mean that handwriting and signature comparisons are fundamentally different, simply that there is often a different emphasis.
General Considerations for Handwriting and Signature Comparisons
For all handwriting and signature comparison cases, three main hypotheses to explain the observations must be considered.
1. The writer of the specimens wrote the questioned material.
2. A person other than the writer of the specimens wrote the questioned material, any similarities to the questioned writing having arisen by chance coincidence.
3. A person other than the writer of the specimens wrote the questioned material, any similarities to the questioned materialhaving arisen because of a simulation process.
Complications which may further arise are considerations of distortion, disguise or self-simulation of the writing in the case of hypothesis (1), combinations of possible effects of (2) and (3), multiple writers etc. The document examiner needs to consider all feasible possibilities which might explain the observations and be aware of the danger of not considering all of these possibilities.
Disguise of Handwriting and Signatures
There are many types of documents on which disguised handwriting appears, from an innocently sent Valentine’s Day card to a note demanding money from a bank teller.
Obvious features of a person’s handwriting, such as slope and/or size, are often changed as a form of disguise. Some people will deliberately introduce letter forms that are markedly different from their usual letter forms and some will use the unaccustomed hand in their writing. In the case of the latter, the writing produced can display the effects of poor pen control and appear untidy, but the subconsciously produced letter constructions and proportions may remain approximately the same, with the possible exception of direction of some strokes. The major difficulty with most disguised writing is maintaining the disguise over a length of text. Where a basic disguise may succeed over a few words, the disguise is often forgotten over a number of sentences with the writer reverting to a natural handwriting style.
A totally different style of writing may also be used as a disguise. For example, if a person normally uses printed script, cursive writing may be tried as a disguise. In this instance however, there will often be examples of the alternative style available for comparison. There are, nevertheless, some forms of carefully disguised writing for which determination of the writer from handwriting comparison methods may be difficult or impossible.
Disguised signatures are written by those persons intending to later deny the signature they have written. Generally the signature produced is so close to the specimen signatures, except for one or two differences, that the document examiner will identify the signature as being genuine despite the attempted disguise (Figs 5 and 6). Self-simulation of a signature or handwriting as a form of disguise can be significantly more difficult or impossible to detect. The writer of a completely simulated signature or piece of writing may be impossible to determine.
Simulation of Handwriting and Signatures
Simulation of handwriting presents a different set of problems for the potential offender. The person intending to copy the writing of another person needs to obtain some specimen writing of the other person. The copyist then has a number of options. The handwriting can be ‘drawn’ or some form of tracing can be used to produce the simulated writing. When drawing the writing, the copyist must stop frequently to check the construction of letters and words used by the person whose writing is being simulated, considerably reducing the speed of the writing process. Where no examples of a particular letter are available, the copyist must use some other form. As a result, the writing thus produced is generally slowly written; the words may display many pauses in writing where none would usually occur, and the letter forms may display many more variations than the genuine writing since the desire to copy the correct letter conflicts with the copyist’s naturalway of writing a particular letter. There may be evidence of the copyist’s naturalhand-writing style in the simulation and other differences from the genuine writing, especially where an attempt is made to write fluently.
Figure 5 (A) Genuine signature ‘C. Lewis’ and (B) slowly written freehand simulation of (A); (C) detail of the letter ‘e’ from the simulated signature exhibiting poor line quality; (D) detail of the letter ‘w’ from the simulated signature showing uncharacteristic pen lift.
Figure 6 (A) Genuine signature ‘C. Lewis’ and (B) quickly written freehand simulation of (A). Signature (B) shows errors in letter proportion and size relationships and an uncharacteristic pen lift in the final part of the signature (C).
Tracing is the second major method of simulating handwriting, with the appropriate letters and words drawn from a pool of writing available to the forger. This method, although it can be effective in suppressing the handwriting style of the copyist, almost inevitably still has the problem of lack of fluency in the writing. Even if at first glance the writing produced appears to be pictorially similar to the genuine writing, it will almost certainly be slowly completed with many stops and pauses in the ink line. Tracing methods can also leave evidence on the questioned document, depending on the method used. For example, traced guide lines in the form of pencil transfers, carbon copy writing and indented impressions can also usually be detected by the techniques available to the forensic document examiner. Should the specimen document from which the simulation has been made become available, this may also bear such evidence in terms of matching of particular letter or word forms, or indentations of the questioned writing.
Signatures contain many fewer letter forms than handwriting but present the same problems to the person attempting the simulation. A further difficulty arises with elaborate signatures as it can be difficult to determine directions and sequence of strokes. As with handwriting, it is extremely difficult to maintain both fluency and the correct forms of the signature components. Where the copyist attempts a highly fluent simulation, evidence of the simulation process is usually present in the form of substantial departures from normalletter constructions. In the case of many traced or freehand simulated signatures, as only one or two signatures are often used as models, the signatures may be far more similar to each other than would be expected of a group of genuine signatures. This is especially true for tracings.
Factors Influencing Handwriting
Many factors can affect a person’s handwriting, and no one person writes so consistently that each letter form is exactly the same. However, the relative method of construction, letter proportions etc. remain consistent within a small range of variation, even if the writing is completed on an uneven surface, at speed or under some other stress. More significant variations in writing style are caused by such factors as age, injuries, illness (mental or physical) with handwriting showing a reduced speed, tremor in the form of erratic impulse movements and there may also be misplaced or poorly joined strokes. Attempted imitation of this type of writing sometimes shows a high frequency tremor which may not be consistent with the tremor of the genuine writer, inconsistent letter constructions or careful retouching of strokes which exceeds the skill of the genuine writer. At times the use of medication can improve a person’s handwriting for a limited period of time, and this is considered by the document examiner.
The only scientific method of determining whether a piece of handwriting or a signature has been written by a particular person whose handwriting may have been affected by such factors as described above, is to obtain as much comparable writing as possible, written when the factors applied. This normally means obtaining handwriting or signature specimens written as close as possible to the date of the questioned material.
Determination of the genuineness or otherwise of handwriting and/or signatures of the infirm can be among the most difficult examinations which the forensic document examiner undertakes, especially when adequate specimen signatures or handwriting reflecting the infirmity are lacking. Nevertheless, useful, if not always certain, determinations can be made by the standard methods of careful examination and comparison with the available specimens, looking in particular for similarities or differences in the more subtle features of the handwriting and/or signature.
Examination from Reproduction Documents
Reproductions of handwritten documents, in the form of photocopies, fax copies and computer-imaged reproductions are often submitted to the document examiner either as questioned or specimen writings. Of necessity, examination from a reproduction provides reduced information. For example, microscopic examination is of little value, except in determining the nature of the copy, since the fine details of writings are lost in the resolution provided by the copy. Nevertheless, useful handwriting comparisons can be made from examination of reproduced documents, particularly good clear modern photocopies, although the examination is restricted mainly to the grosser pictorial features of the writing. Suitably qualified conclusions are usually expressed, along with warnings that it cannot necessarily be assumed that a true reproduction of an originaldocument has been examined as photocopy or computer manipulation may sometimes be accomplished without leaving evidence of the manipulation in the resulting reproduction.
Document examination encompasses much more than comparison of handwriting and signatures. Document examiners also consider the inks and printing seen on the paper, the paper itself, folding, stamps and seals and writing impressions. All of these, together with the handwriting and signatures, go towards proving the provenance of any particular questioned document.