A common error when asking for an expert test is only requesting the authenticity or otherwise of the existing signatures on the document. Despite case law on the evidentiary value of a photocopy, it is also true that there are often ways in document analysis to discover:
It is the chairman's signature, but the chairman did not sign the document.
1. If the document has been tampered with or otherwise,
2. The connection between the different copies comprising a contract or document,
3. If they come from an original or a manipulated (master) document, and perhaps most importantly
4. How the document was manipulated, which can certainly be very important in solving the case.
In short, our experience has shown us that there is a lot of data in photocopied documents that can shed light on how they were created and the signatures they include. This technically-proven evidence can help the defence of a client. If you need expert handwriting tests, ask a specialised laboratory for the terms and scope of the test.