Abstract: Unauthorized alteration of a document can be avoided in a secure document that includes a substrate (10) defining the body of the document. Indicia (24, 26, 30, 32, 36 and 40) located on the substrate (10) designate an area (42) to receive variable information by an impression. The variable information is that whose alteration is to be avoided. A chemical, carbonless imaging system (44) is disposed on the substrate (10) at the area (42) and is operative to form a visible image upon receipt of an impression and a transparent film (46) is located on the substrate (10) to cover the area (42). As a consequence of the construction, any attempt to alter an image appearing on the film (46) will be apparent from the original imaging of the chemical carbonless imaging system (44) or by smudging thereof indicating an alteration attempt.