This invention concerns a security with identifying marks in the form of colour patterns, which are printed in the substance of the paper layer, and a method for manufacturing the same.
In the sense of this invention identity papers, credit cards and documents stand for all kinds of securities, such as banknotes, cheque cards, passports, cheque blanks, share certificates, postage stamps, travel tickets or the like. Hereinafter, the simplified term security paper or security therefore always includes documents of the aforesaid kind.
The aforementioned documents are very valuable and must be capable of identification beyond all doubt with respect to their origin and originality, since their material value is merely a fraction of their trade value. Identification is carried out in many ways including the use of identifying characters or marks specially intended for checking their authenticity. In ideal cases, these identifying marks cannot be copied nor forged, or at least only at great expenditure. The presence of such identifying marks in the manner intended thus vouches for the genuineness of the security paper in question. The more an identifying mark can be described as being "non forgeable" and "not capable of being copied", the greater its value for guaranteeing its authenticity.
Heretofore, such identifying marks have been most valuable which can only be incorporated in the security paper during its manufacture. Examples of such marks are, for instance, watermarks, security threads, chemically reacting additives and mottled fibres. These characteristics or marks are particularly suitable for casual scrutiny of security papers, this being the normal method of checking their authenticity. Although these marks can be detected visually, they provide for a high degree of security because paper provided with them can only be manufactured in expensive machines which are out of the reach of forgers and which are unprofitable for forgery if purchased or copied.
A further enhancement of security can be brought about by incorporating the identifying marks only in exactly defined locations in the paper. Besides the difficulty of producing the identifying mark, a potential forger has then the additional difficulty of incorporating it in an exactly defined location of the paper. This further increases his expenditure and reduces the profitability of the forgery.
For practical purposes, such measures are mostly taken in the case of the manufacture of very valuable securities, such as banknotes. Here, it is usual to place the watermark or security thread in certain locations of the security paper. Moreover, patent literature recites the use of mottled fibres in certain locations, these being, more particularly, in the form of strips.
In contrast to this no attempt has yet succeeded to localise chemicals, dyes or other identifying means in any desired location in the web of paper. Such identifying substances are therefore added either to the paper stuff itself or when its surface is being prepared. Therefore, they are always randomly distributed in the whole of the paper stuff or on the total surface of the paper.