Banknotes incorporating security devices

摘要: A security document (1), such as a banknote is formed from sheet-like substrate (10) of clear plastics material with layers (13, 14, 15, 16) opacifying ink applied to the surfaces (11, 12) (10). The (1) includes device (20) which at least partially obscured by 14) on first surface (11) (15, second (12) are in manner so leave "half-window" area uncovered through visible one side (1). may extend transversely outside half-window and be transmission, enabling different contrasting effect observed both sides document.