What is micro lettering on a banknote?

Answer 1

Microprinting is a technique intended to discourage counterfeiting because most common printing techniques can't handle really tiny images.

Use a magnifying glass and you can read the names of U.S. states along the frieze of the Lincoln Memorial on the reverse of the U.S. five-dollar bill. On the twenty-peso note of Mexico just above the number 20, you can read the words of Benito Juárez, "Que el pueblo y el gobierno respeten los derechos de todos. Entre los individuos, como entre las naciones, el respeto al derecho ajeno es la paz."

May the people and the state respect the rights of everyone. Between people, as between nations, peace comes from respecting the rights of others.

If microprinting were written any larger, people might have to take it seriously.