20. The method according to claim 19 , wherein said security features include intaglio patterns, line offset patterns, letterpress patterns, optically-diffractive structures and/or combinations thereof.
19. A method for producing security documents, in particular banknotes, comprising the step of designing security features to be printed, applied, or otherwise provided on the security documents, wherein said security features are designed in such a way as to optimise an authenticity rating computed according to the method of claim 1 by producing a characteristic response in the said at least one scale sub-space.