1. A method of determining whether a document is likely an original document, the document comprising a first steganographic watermark and a second steganographic watermark, said method comprising: reading a first characteristic related to the first steganographic watermark; reading a second characteristic related to the second steganographic watermark; reading a third characteristic related to the document's physical condition; and with reference to the first, second and third characteristics, assessing whether the document is likely an original document.