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(11) | EP 0 474 404 A3 |
(12) | EUROPEAN PATENT APPLICATION |
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(54) | Substrates having revealable, non visible messages |
(57) 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. |