Security Inks.

With the advent of the color copiers, good quality counterfeiting of all types of checks, securities, winning tickets, etc., is now available to a much larger group of people. Ink systems are being developed which will: 1. Cause the word copy or void to appear on every color copy. 2. Put a non-noticeable mark on every document which can be detected chemically, electrically, magnetically, thermally, or by radiation, thereby differentiating the original from its copy.