Questioned document analysis will often involve the study of handwriting, typewriting, imprinted documents, alterations, ink, paper, and writing instruments. The primary aim is to gain as much information regarding the document as possible without damaging or altering the document if possible. Individuals may fraudulently manipulate or forge documents for a number of reasons, including monetary gain, identify fraud, benefit fraud, the concealment of information, or as an alibi.
Forensic graphology, the study of handwriting, is based on the idea that no two individuals have exactly the same handwriting. It closely examines the potential differences in people’s handwriting, with variations existing in slope, speed, angularity, pressure, letter dimensions, character spacing, connections, pen movement, finger dexterity, writing skill, grammar, spelling, punctuation, margins, crowding, phraseology, and alignment. A common misconception of graphology is that it can determine personal details about the writer, such as their sex and age. This is not true. It can however give insight into the likes of the writer’s frame of mind, mood, motivation, intelligence, and emotional stability. It may even be possible to assume the writer’s nationality from their handwriting, as certain character constructions are more common in particular parts of the world.
Samples of the suspect’s handwriting will be collected to compare to that of the suspect document to conclude whether or not the suspect was the author. Even if a suspect attempts to alter their handwriting, key characteristics will be visible, especially if the individual was required to write for a long period of time. As many handwriting samples as possible should be obtained, preferably pre-existing, fairly recent exemplars produced in the course of day-to-day business. If possible, the samples should contain words or phrases matching those found in the suspect document. It is also important that like is compared with like. In other words, only block capitals should be compared with block capitals, and cursive with cursive. It should be taken into account that natural variation will occur in handwriting, due to the likes of illness, stress, drugs, and similar. Many forged signatures were originally traces of the genuine one. In these cases, faint pencil lines from the tracing may still be visible under the ink. A lack of flowing consistency in the signature may also be a sign of forgery.
Impressions of handwriting may be left on one document if another document was written on whilst placed on top of it. These indentations may be visible following the application of oblique lighting. The Electrostatic Development of Indented Writing Impressions test can visualise also visualise this latent evidence.
Word Processed Documents
Word processed documents are printed onto paper by laser, ink jet, or dot matrix printers. Laser printers work in a similar way photocopiers do. They contain a photosensitive drum which, when it becomes charged, produces an electrostatic negative of the image to be printed. Negatively charged toner sprinkled on the drum will cling to the charged areas before being pressed on the sheet of paper, producing the document. Laser printers do not produce many distinguishing characteristics on their documents.
Ink jet printers use grids of tiny nozzles which, when heated, drop ink onto the paper. Ink jet printers often produce print with a somewhat ragged appearance which is easy to spot. Though it is easy to recognise documents produced by ink jet printers, it is not easy to differentiate between documents.
Dot matrix printers use a ribbon with a number of pins to strike the paper, transferring the ink. Due to their large number of freely moving parts, when pins become damaged they will leave behind individual marks on the paper. These unique marks may be linked to a particular printer.
Examination of Inks
It is often possible to distinguish between different inks, and therefore establish whether the same ink was used to write two documents, or whether alterations were made in a different ink.
Thin layer chromatography can be used to separate the components of a sample and ultimately determine whether two ink samples are the same. However this method is not always beneficial, as ink compositions are not always drastically different. As different inks may appear different under certain wavelengths of light, illuminating an ink with such light can be used to distinguish between them. Higher wavelengths of light may even render some inks transparent, potentially revealing underlying markings.
Examination of Paper
The examination of the paper itself can help establish whether two samples are of the same composition or not. This involves studying the size, thickness, density, colour and finish of papers. Some manufacturers will incorporate biological fibres, optical brighteners, and watermarks into their paper, adding distinctive features that may be useful in a forensic investigation.
Erasures, Alterations & Additions
It may often be necessary to determine whether any modifications have been made. Under oblique light, erasures may be visible, even if the original material is not observable. Erasures made with a rubber will often leave behind minute rubber fragments, detectable by sprinkling a powder of dyed Lycopodium spores (lily) on the document. The use of ultraviolet or infrared light sources may visualise erased ink, particularly if the ink has been erased using a chemical solvent.
Criminals will often attempt to forge bank notes, bank drafts and passports for monetary gain, though fortunately all of these are now produced using methods which deter counterfeiting. Papers are used which will change colour if certain chemical are applied or if erasure is attempted, preventing manipulation. Particular coloured fibres, complex patterns, and specialised inks are used in the documents, making forgery extremely difficult and expensive.
On many occasions a document is presented that is supposedly of a certain age and value, something which the forensic document examiner may be required to prove. The age determination of the paper or ink can at least establish whether they raw materials used were from the claimed time period. By testing the ‘dryness level’ of the ink, the examiner may be able to determine how long the ink has been on the paper. This method can also discover whether the entire document was written at the same time, over a long period of time, or if slight alterations or additions were made. Some inks may even contain chemical date tags indicating the exact year in which they were manufactured.