Subject:  07/95 New U.S. currency.GIF
Author:  Laurie Grace
Uploaded By:  CHansen598
Date:  6/7/1995

File:  schaf01.GIF (124217 bytes) 
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From the July 1995 issue of SCIENTIFIC AMERICAN

Protecting the Greenback

by Robert E. Schafrik and Sara E. Church

This 640 x 413 pixel image shows that counterfeit deterrence relies on a combination of features in a single note. Faces are highly recognizable, especially when printed by the intaglio method, renowned for its ability to create fine detail (highly magnified at lower left). Pentagonal planchettes shimmer iridescently, and special inks can shift color, for example, from green to orange, with viewing angle. A security strip and a watermark are visible only in transmitted light. A bull's-eye-like figure generates a conspicuous moire pattern when copied by digital means. (The fantasy collage shown here was not based on any planned U.S. currency.)