Abstract: A hidden image game piece is formed on a transparent or translucent substrate which is part of an optical disc (e.g., a CD or DVD). The hidden image can be used to contain a “key” which is required to gain access to the data contained on the optical disc, thereby aiding in the prevention of that type of piracy of the content of the optical disc which could be accomplished by a simple disc-to-disc copy.

Abstract: A hidden image game piece and a method by which a hidden image game piece is produced. A first pattern of colored ink is deposited on a transparent or highly translucent substrate at 110-180 density, forming the image which is to be hidden. Then a second pattern of colored ink, of a different color than first pattern's ink, is deposited upon the substrate on top of the first pattern, at 90-170 density. When the game piece is flooded with additive light of the same color as the second pattern's ink, the previously concealed image, composed of the first pattern's ink, becomes perceptible. Because a transparent or highly translucent substrate is used for the game piece, and because the density of the ink application is controlled within specific ranges, this game piece may be used with a computer monitor, or with other low-intensity sources of additive light.