Patent ID: 7354072

Claim:
An authenticity determinable printed matter comprising a background image portion and at least one message image portion printed on a surface of a base member, wherein the background image portion has a first line drawing which is arrayed in a first direction and printed by an ink with a specular gloss to have an ink layer thickness, and the message image portion has a second line drawing which is arrayed in a second direction and printed by the ink with the specular gloss to have the ink layer thickness, and wherein when the printed matter is observed from a direction in which a total light amount as a sum of a specular reflection light amount and a diffusion light amount in the first line drawing substantially equals that in the second line drawing, the message image is rarely visually recognized, when the printed matter is observed from a direction in which the total light amount in the first line drawing is different from that in the second line drawing, the message image is visually recognized, when an observation angle is changed, a lightness and/or color of the message image continuously changes, when the total light amount in the first line drawing is larger than that in the second line drawing, the background image portion has a higher lightness than the message image portion, and the message image portion is visually recognized as a positive image, and when the total light amount in the second line drawing is larger than that in the first line drawing, the message image portion has a higher lightness than the background image portion, and the message image portion is visually recognized as a negative image.