FDE white paper

Forged or not? How to investigate a signature

Interview with Forensic Document Examiners Andrea Devlin, Michelle Novotny and Dr Steven Strach, Forensic Document Services Pty Ltd (FDS in the following).

In Germany, the police clarification rate for forgeries of documents is around 80, 85 percent. So, forensic document examiners (“FDEs”) are obviously doing a very good job. Is it that easy to find out whether a signature is or is not genuine?

Yes and no. As people cannot write with machine-like precision, each signature will vary. Therefore, FDEs examine a questioned signature together with known signatures and compare corresponding signature elements: structural (number, direction and sequence of pen strokes), pictorial (shapes, proportions, spacing, and alignment), and dynamic (apparent speed, and pen pressure). The goal is to determine whether the features in the questioned signature are or are not within the range of variation of the known signatures.

Why is it so important to know if a signature is authentic?

A signature on a document represents far more than just a version of a name on a document written by a person. A signature represents an authority for a specified course of action that is stated on the document and should be a form of a person’s name that is intended to be unique to that person. As such it could be considered the most important component of any person’s handwriting. Financial implications of a single signature can range from small amounts of money, to one’s whole estate and in some cases to billions of dollars. Common kinds of documents submitted for signature examination to FDS include loan documents land title documents, authorities, power of attorneys and wills.

“The goal is to determine whether the features in the questioned signature are or are not within the range of variation of the known signatures.”

Are there kinds of “typical” cases for signature fraud?

Signatures on documents relating to problematic financial transactions are often disputed by the person who suffered the financial loss. Take loan documents: In some cases, the borrower denies having signed the document, when the lender tries to recover missed payments. We have had many cases where we have found evidence of signature simulation and in some of these it has transpired that the parents’ signatures have been “forged” on the loan documents by their grown children.

Testator signatures on Will documents are often disputed by family members. Unfortunately, when the Will belongs to an elderly or infirm person, we often have to deal with poor writing quality and a lack of specimen signatures close to the apparent date of the Will. So, sometimes the result is indeterminate.

How does an FDE work? What are different steps or actions to verify the authenticity of a signature?

It is essential that we are provided with as many genuine specimen signatures as possible. We then undertake a detailed macroscopic and (for originals) microscopic comparative examination –- to ascertain the precise method of construction of signature components, their variations, how various components relate to one another and the fluency of the writing.

The examiner then concludes on the qualitative likelihood that the questioned and specimen signatures were or were not written by the one person. It is important to realize that signatures are not simply determined as being genuine or forged. So, even when evidence is found of simulation, it can be difficult or impossible to distinguish between “self” simulation and simulation by another person because essentially the same processes are involved.

“As technologies advance, the scope of work of a FDE expands.”

Usually, signatures are ink on paper. But what about electronic signatures? Are they easier to examine?

This is covered in our May 2018 White Paper “Evaluation of Wacom’s Electronic Handwritten Signature Technology” . In summary, examinations based on electronic signatures were found either to have an advantage or were at least equivalent to examinations of ink on paper signatures. They may not necessarily be easier to examine, in terms of the time taken to examine them, as the methodology for examining electronic signatures is partly different to that of examining ink on paper signatures and provides much additional information not quantifiable in examining ink on paper signatures. More research needs to be undertaken to determine whether examination of electronic signatures results in stronger conclusions.

So, does technology help you to do your job or improve your results?

Obviously, it provides a means for FDEs to undertake detailed examinations of both ink on paper and electronic signatures, and of documents in general. Our field of forensic science is broad and as technologies advance, the scope of work of a FDE expands. Today, not only are we called upon to examine matters involving ink on paper signatures but we are also called upon to examine electronic signatures and printed computer generated documents.

How will the examination of signatures develop? Will technology help to avoid forgery in the future?

This is a large and potentially speculative area. However, we are confident that the electronic signature technology being developed by Wacom has the potential to improve significantly the security of the traditional signature.

“It is wise to develop a signature style that is not easily imitated.”

Any recommendations on how you can prevent your signature from being forged?

A key factor in making one’s signature “forgery-proof“ is to make it complex – simple signatures are, at least theoretically, easier to simulate. The complexity of a signature can be assessed qualitatively by considering such aspects as the total line length, the number of turning points in the line, the number of overwritings or line intersections, and the continuity of pen movement. It is also better not to change the signature style once a design has been decided upon.

Forensic Document Services Pty Ltd (FDS) is an Australian private practice laboratory with a team of trained and experienced forensic document and handwriting examiners, among them our interview partners:

  • Andrea Devlin, a Forensic Document and Handwriting Examiner, based in FDS’ Sydney laboratory
  • Michelle Novotny, a Senior Examiner and Managing Director of FDS, based in FDS’ Sydney laboratory
  • Dr Steven Strach, a Senior Examiner at FDS’ Canberra laboratory


Are electronic handwritten signatures easier to analyze?

A recent study found an answer to this question: Yes, at least in some respects. Forensic document examiners compared ink on paper signatures to electronic signatures which were simultaneously captured using a Wacom Signature Pad. The examiners analyzed features like speed, structure, direction of stroke and even “pen up” movements in a total of 180 samples.
The results of the study indicate that forensic document examiners can rely on the analysis of an electronic signature at least as well as on the traditional analysis of an ink on paper signature. Furthermore, the new technology offers advantages, for example the ability to play back the track of the signature in real time or the tracking of the pen above the pad, producing “pen up” data.
The findings also provide knowledge that benefits the development of electronic signature devices and software. The aim is to make the technology secure against forgery of documents.

Evaluation of WACOM’S Electronic Handwritten Signature Technology

A Whitepaper by Dr Steven Strach, Michelle Novotny, Andrea Devlin, February 2018

Download full text

What is the whitepaper about?

The whitepaper addresses the following question: Can electronic signatures written using Wacom’s STU-430 Signature Pads be usefully examined by a professional forensic examiner using Wacom SignatureScope software with a view to addressing their genuineness and, if so, how does it compare to the examination of ink on paper signatures?

Who are the authors?

The authors of this whitepaper are forensic document examiners (FDEs). This profession uses scientific analysis and examination techniques to decide, for example, whether a signature is genuine or forged.
The whitepaper and its underlying investigation was funded by Wacom Co., Ltd. Tokyo Office and the examination laboratory Forensic Document Services Pty Ltd. (FDS)

What was examined?

The object of investigation consisted of 15 signatures in each of six names, as ink on paper signatures as well as the corresponding electronic signatures. A total of 180 individual signature examinations and 60 comparison exercises were undertaken by two primary examiners. Also, two secondary examiners peer reviewed the work of the primary examiners and a fifth examiner compiled the study material and provided the basic analysis of the primary examiners’ results.

Which examination method was used?

As the ink on paper signatures were examined following the standard procedures for signature examination, the team used a draft methodology for examining electronic signatures, developed by FDS. The draft methodology defines certain signature features in order to compare electronic signatures and ink on paper signatures directly.

Which signature features were evaluated?

The examiners analyzed pen speed, pen stops, relative pen force, pen strokes, pen lifts, pen orientation, signature line smoothness, orientation with respect to the signature line, width, height and area of the signature as well as other pictorial features. Significant use was made of the “pen up” information, such information being unavailable in the ink on paper signatures.

What are the main results?

According to the study, examinations of electronic signatures are either equivalent or have an advantage compared to examinations of ink on paper signatures. Most of the signature features were easy to evaluate with the help of Wacom SignatureScope software. Exceptions were pen orientation and signature line smoothness.
A clear advantage of the electronic signature examination was the possibility of observing and taking account of a further, normally unseen dimension of many signatures, i.e. being able to track the “pen up” movements above the pad within the signature.