The popularity of TV shows such as CSI have brought forensic science into the living room. One of the downsides of this however is that client expectations on what is possible in certain areas of forensic science often greatly exceed what can actually be done. Forensic scientists and legal professionals have dubbed this the “CSI effect” and in Forensic Document Examination its manifestation is in the area of ink dating.
Barely a week goes by were I don’t have to field an enquiry on this topic. Usually the enquiry involves a signature on a will or a commercial document. The signature itself may not be in dispute but the actual date of signing may be critical to the resolution of the matter. Often the client believes that the document can be easily analysed to give an exact date the ink was placed on the paper.
Unfortunately this is a complex and specialist area requiring chemical analysis of the written ink by a Forensic Chemist who will take a “punch” of the ink from the document, perform tests in an attempt to determine either the chemical composition of the ink or the relative “dryness” of the ink on the paper. This testing has the disadvantage that the original document must be released to a laboratory, something that is problematic for many legal documents and potentially expensive for the client. Depending on the scientific method used, some results of such testing are of questionable value, and have been successfully challenged in court. To determine the commercial availability of a specific ink based on its chemical constitution, ink reference libraries do exist, but they are generally the preserve of government agencies and as such are not available to the vast majority of professionals working privately in the FDE field.
Other techniques offer more possibilities. Examination of the document as a whole may offer clues to its age. The type of print method used, typeface, paper, stamps or seals can be examined. If the document is a form or template, investigations can be made as to the version of such a template and what date it became available. Headed paper may contain the names of company directors or company logos, both of which change over time.
Another possibility is to try and “time bracket” the signature in question. If enough comparison signatures are available from the individual concerned over a long period in time, then they can be evaluated to determine how these signatures may have changed over time. Some of these changes can be quite gradual and subtle in nature. The questioned signature can then be compared with the pattern of the known signatures to see whether it is consistent with the date it was purportedly signed on.
A Forensic Document Examiner will use all possible methods at his disposal to try and solve this difficult problem for the client – just remember we are not on TV!