The answer varies depending on the specific issue being addressed. That is, it depends on whether the issue relates to authorship of handwriting/signature, or something else.

In situations where the question requires only an examination and no comparison against a standard reference, e.g., examination for indentations or detection/decipher of an obliteration, there may be no need for any specimen samples since such work is conducted using only the questioned item. However, if the issue at hand relates to the source or authenticity of a document (or some aspect of the document), then specimen samples are almost always required to conduct a comparative analysis and evaluation.

Precise instructions for obtaining appropriate specimen samples, either ‘collected’ or ‘request’ in nature, are available upon request. The following are some general guidelines for handwriting authorship issues, signature authorship issues, and for other examination types.

For authorship issues involving questioned handwriting of an extended nature (meaning writing that is a full sentence in length or more), it is generally beneficial to obtain as much extended specimen writing, of a comparable nature, as possible.⁴ However, a reasonable minimum for most writers would be three to five repetitions of the same or similar text.⁵

It is very important to have writing of a type similar to the questioned samples, i.e., cursive to compare to cursive; hand printing to hand printing, block lettering to block lettering, etc.  It is also important to have writing samples with comparable (i.e., similar) textual content; ideally, the same text written multiple times.  As a minimum, the specimen text should include the same letterforms and combinations, if not precisely the same text.

Lastly, specimen samples should be reasonably contemporaneous to the questioned document.

For authorship issues involving a questioned signature, it would be ideal to obtain at least 15 to 20 exemplar signatures, written on or about the date in questionAs with extended handwriting, it is generally beneficial to have as many samples as possible, with the total number becoming more critical in cases that involve age, illness, or impairment since these factors introduce additional variation into the writing act. 

Ideally, specimen samples should be roughly contemporaneous to the questioned document. Again, this is particularly important in cases involving age, illness, or impairment of any type. 

It is also important that the signature be written in the same name so, for example, signatures written in the name “John Doe” cannot be compared to those written in the name of “Peter Brown”. This can be problematic when a suspect in the matter has a completely different name than the one in question.

Single/isolated questioned signatures can be compared but, depending upon the graphic complexity of the signature, this will likely place significant limitation on the opinion. The goal is to adequately characterize the habits and range of variation possessed by the writer. With fewer samples, the process becomes more uncertain and, ultimately, this would tend to produce a more inconclusive result.

This includes the examination or sourcing of photocopiers, printers, faxes or typewriting; basically, any device capable of producing a document.

For these examinations, original documents are almost always required.⁶

It is best to obtain the suspect machine, if possible, along with all related accessories (such as, daisywheels, typeballs, ink cartridges, paper tray, cables, user manuals. When doing so, pay attention to accessories like ink ribbons or cartridges that might have been discarded, but still be present in recycle or trash bins.

When a suspect machine cannot be obtained, then a meaningful examination may be possible using appropriate historical samples produced using the device and obtained from appropriate records. For this approach, as many samples as possible should be acquired, with attention paid to locating items with comparable text (e.g., style, font, letters/numerals), as well as multiple samples, if possible.

It is also important to obtain and include samples of any forms, letter head, paper possibly used to produce the questioned documents.

Other related FAQs:

• What purpose do specimen samples serve?
• What is a specimen/exemplar?
• What type of specimen samples do you need?
• How is proof of specimen material achieved?

1. In this context, handwriting includes handprinting or block lettering of an extended nature.
2. The amount required really depends in part on the maturity and skill displayed in the writing.  In general, the more highly skilled and developed a writing, the fewer samples may be required.
3. One obvious exception involves examinations of the reproduction itself where the question focuses on its manner of production, or occurrences to it; rather than the 'original' item.
4. In this context, handwriting includes handprinting or block lettering of an extended nature.
5. The amount required really depends in part on the maturity and skill displayed in the writing.  In general, the more highly skilled and developed a writing, the fewer samples may be required.
6. One obvious exception involves examinations of the reproduction itself where the question focuses on its manner of production, or occurrences to it; rather than the ‘original’ item.