Forensics labs are frequently asked to examine documents to determine if they have been altered or forged. An altered document is an original, valid document that has been changed in some way. For example, one common type of altered document is a cheque in which the numbers have been changed to increase the amount drawn. A forged document is one that is created from scratch to masquerade as a valid document, or a valid document to which a page or pages has been added to alter the meaning or intent of the original document. Forensic document examiners use several methods to determine the validity of a questioned document. The first step is always to examine the document with the naked eye and under low magnification. A surprisingly large percentage of forgeries are so crudely done that the forgery is obvious even on cursory examination. If the document passes this first “sniff test,” forensic document examiners have many other tools available.