Jacob Perkins (1766-1849) was an American inventor; he made machines for making nails and boring out cannons and pioneered the developments in heating technology that led to the refrigerator.
However, in the early 1800s, he began working on a method of security printing that would be all but impossible to forge.
He picked the right time. The world’s treasuries were switching from bullion to paper money, while the Pax Britannica had led to a massive increase in world trade and manufacturing activity, requiring corporate bonds, share certificates and other official documentation.
The job posed two major challenges.
Firstly, to create a design intricate enough to defeat even the most expert forgers.
Secondly, to reproduce that design throughout the extended print runs that treasuries require, creating literally millions of perfect copies.
The first problem was solved by engineering and the development of engine-turning machinery, which created patterns called Guilloches. The most sophisticated of these was the Rose Engine lathe, which created similar patterns to a spirograph. Perkins patented a modified machine, which created the frame and background for all the lines engraved.
The second solution was metallurgical. A master die was cut in soft steel, which was hardened to the extent that ordinary metal tools wouldn’t even scratch it. The die was then used to make impressions in a transfer roller – also of soft steel. This again was hardened and used to ‘rock in’ 240 impressions on the printing plate
