| abstract |
A hidden entry system comprises a document having a first substrate bearing a localized latent image spaced apart from a removable image-developing device comprising a second substrate having a first surface and a second surface, the first surface of the second substrate bearing a chromogenic composition comprising an image-forming co-reactant, the image-forming co-reactant being a chromogen or a color developer, the second surface of the second substrate bearing a pressure-sensitive adhesive. The image developing device is in superposed relation with the first substrate with the pressure sensitive coating being releasably attached to the first substrate. |