How is it that handwriting can be identified as belonging to one person and not another?

The unconscious, individual and habitual features in handwriting, considered in combination, contribute to the uniqueness of one’s handwriting and constitutes a means by which the handwriting of one writer may be discriminated from that of another.

Handwriting is the end result of a long process that starts with the imitation of a penmanship model when we first learn to write. Initially, these writings are very crude and require substantial conscious effort. Over time, the writing action requires less attention, manifests increased proficiency, skill and departures from the copybook form. These departures in the form (i.e., personal changes, individual characteristics or idiosyncracies) may be obvious or inconspicuous with the author being unaware. In the mature writer the physical act of writing becomes an automatic or unconscious action. During normal writing a persons conscious mind is concerned with the words being written and not on how it is being written. Furthermore, the natural handwriting of a mature writer will appear pictorially similar and does not drastically change from sample to sample. An action that is repeated in much the same way and without thought is referred to as a habit. Thus, handwriting is considered a habitual action.

Forensic Document Examiners study and compare the unconscious, individual and habitual features in handwriting for the purpose of distinguishing or associating writing that is in dispute.

What is needed for a handwriting comparison?

It is preferable that the submitted documents be originals. The known material should also be comparable, contemporaneous, sufficient in quantity to assess the author’s range of variation and be collected from normal course of business and/or requested by dictation.

Can all handwriting be identified?

Handwriting may not always be identifiable to a specific writer, however in the vast majority of cases it is possible to reach an opinion as to identification, elimination or somewhere in between. Factors that may contribute to a less that definite opinion and result in a qualified opinion include:

          writing that lacks sufficient identifying characteristics (i.e., writing that 

             mainly exhibits class characteristics and few individual characteristics)

          limited quantity of questioned and/or known writing

          distortion or disguise in the questioned and/or known writing

          lack of comparable or contemporaneous exemplars

          submission of poor quality reproduced documents

Are handwriting and signature examinations possible on reproduced documents? Are there any limitations?

In most cases the examination of handwriting and signatures from reproductions is possible, however it is preferable to use original documents when feasible. Examinations based solely utilizing copies may be limited and the opinions “qualified”.

While an examination of individual letter forms, letter connections and general pictorial appearance is possible, certain elements of execution may be difficult to observe. Furthermore, by using a photocopier, scanner or facsimile machine the possibility of transferring a genuine signature to form a fraudulent composite document must also be considered.

Lastly, on reproduced documents other potential forensic evidence such as indented writing impressions, alterations, obliterations, erasures, additions, ink differentiation, watermarks, printing methodology or latent fingerprints may be impossible to observe, recover or record.