Process for applying a metallic image in register to a document of value

DETAILED DESCRIPTION The instant invention is directed to a process for preventing the counterfeiting of valuable documents by applying extremely thin layers of metal to the document at predetermined locations.
Application of the thin metal layers to a valuable document prevents counterfeiting by photocopying techniques since the metallized surface reflects both ultra-violet and infra-red light.
Therefore, the portion of the document covered by the metallized surface will not be reproduced when the document is copied.
Counterfeiting by other methods is also made extremely difficult because the technology necessary to perform the metallization process is only available to security printers and the like and not readily obtainable by the general public.
Finally, and most importantly, the inventive process creates a "ghost image" on the metallized surface which is similar to the "latent image" utilized in the prior art discussed above.
The "ghost image" on the document seems to appear and disappear as the document is viewed from different angles making a genuine document easy to identify by a lay observer.
Also, of course, since the "ghost image" effect is lost when copied the difference between a genuine document and a counterfeit photocopy is striking.
The basic underlying process by which a metallized surface is applied to a document substrate is set forth in U.
S.
Pat.
No.
4,215,170 granted to D.
Entique Vilaprinyo Oliva on July 29, 1980 and the teachings of this patent are hereby incorporated in this application by reference.
Briefly the process described in U.
S.
Pat.
No.
4,215,170 involves an extremely thin coat of metallic particles on a finely finished transfer agent in a conventional vacuum chamber.
The transfer agent is preferably in the form of an elongated web of plastic material such as untreated polypropylene, polyester, polyethylene, polyvinyl chloride or the like which may be fed by roller means.
The exact method of metal description is described in U.
S.
Pat.
No.
4,215,170 and as stated therein metallic layers with a thickness substantially less than 500 Angstroms can be deposited on the transfer agent