Forensic Handwriting Analysis
Each person writes a certain way. In forensic handwriting analysis, document examiners analyse samples to determine whether the handwriting of multiple specimens was written by the same person or not. Forensic document examiners are also referred to as handwriting experts, this term also applies to graphologists (who use handwriting as a way to analyse personality traits of an individual).
Handwriting Analysis in Forensic Science
The majority of the work undertaken by document examiners in the forensics field is related to the analysis of handwriting. Handwriting analysis works on the principle that the writing of each person is unique, but that the writings of each person do have a natural variation range and that this is actually a feature of their handwriting.
As a result of this, handwriting can sometimes be used as an individualised means of identification. This usually depends on whether there are sufficient quantities of handwriting are available to be compared with questioned handwriting.
Why is handwriting unique?
The actual process of writing is quite complex. It's a motor task which must be learnt and generally starts in individuals at around the age of 4 when they first begin tracing letters.
Throughout childhood, the skill of writing increases and begins to take on individualised characteristics which differentiate from other peoples handwriting. The main period where these characteristics form is during the teen years. Adult handwriting usually stays the same, with only minor changes until the person becomes elderly and begins to lack pen control, at which point it will change significantly again.
The three basic types of handwriting categories are block letters, cursive and script.
Block letters refers to uppercase unjoined writing. Cursive refers to lowercase joined writing and script refers to lower case unjoined writing. The majority of people write somewhere between cursive and script and signatures are considered a specialised form of handwriting and as such, are examined separately to block, cursive and script.
Analysing handwriting samples
In order for a forensic document examiner to make a meaningful comparison between two samples of handwriting, the type of handwriting must be the same yet allow for natural variation. Individual letters are examined and analysed, as well as groups of letters and words. The document examiner compares all the letters and characters present in each sample, and using a microscope they examine the construction, proportions and shape of the letters and characters. This is necessary to see whether both the directions of pen strokes as well as the order of pen strokes match the samples. The direction of pen movement can reveal whether the person who wrote the sample is left or write handed (for example, right handed individuals tend to write the letter 'o' in an anticlockwise direction, whereas left handed individuals generally write the letter 'o' in a clockwise direction). Other features examined include the connections between letters, if there are any, the slope of the handwriting as well as general features such as word or letter spacing, date style and overall arrangement.
Natural variation must be present too. The handwriting of any individual is never completely identical, though retains all their individual writing characteristics.
There are two types of specimens used for handwriting analysis:
Non-request: which consists of samples or documents that were written without prior knowledge that they would be used as a sample for analysis and, if possible, should be written as close to the timeframe where the other sample which is being analysed was written.
Request: where the sample of handwriting was produced upon request. Generally this type of sample will lack the natural variations found in non-request samples. Other issues with this type of sample include an individual attempting to disguise their handwriting, or variations occurring due to stress at the time the sample is prepared.
Signatures are significantly different from handwriting samples, as they are highly stylised and often illegible. Since they are used as a means of personal identification, the repeated use of them means that most people write a signature automatically and without much thought at all. Natural variations will still occur though.
Characteristics of forged signatures include:
Unnatural pen lifts
Pen strokes with blunt ends
Evidence of retouching
Difference in scale
Incorrect proportioning of letters
Unnatural similarity between two or more signatures
Forensic handwriting analysis is a complex process which involves analysing many different factors in order for a comparison to be made between samples. Other factors which are examined during the process include writing implements such as paper, or inks and what pens they are commonly found in. Inks are also able to be dated, meaning that a rough timeframe for when they were used to write a document can be established.