SUBSTRATES HAVING REVEALABLE, NON-VISIBLE MESSAGES

摘要

The invention provides a substrate having an invisible message that is revealable. The substrate is formed of a recording sheet upon which is a first-image forming component that is capable of reacting with a complementary image forming component to produce a visible reaction product. The first image component is arranged on the recording sheet in a pattern corresponding to the positive or negative image of a desired message. Alternatively the recording sheet has a desensitising component on it that is arranged in a pattern corresponding to the positive or negative image of a desired message. In use, the desensitising component prevents the formation of the visible reaction product when the complementary image forming component is applied on the first image forming component.