A self-verifying security document, such as a banknote, comprises a flexible sheet formed from a plastics substrate bearing indicia. The sheet has a window of transparent plastics material that includes self-verification means for verifying a security device provided at a laterally spaced second portion of the sheet when the sheet is bent or folded to bring the window into register with the security device. The self-verification means may be an optical lens for reading an area of microprinting. In another embodiment, the self-verification means may be an optical filter for viewing an area printed with metameric inks. In other embodiments, the self-verification means and the security device may be polarizing windows or Moire inducing patterns.

 
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> Laminate sheet for security booklets and method for making same

> Security paper

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