On notes of 100 pesos and above, the denomination is printed in color-shifting ink in the top right corner.

Located in the bottom right corner on the face of the bill, the number "20" is made of color-shifting ink.

The $100 note's "bell in the inkwell" freedom icon uses color-shifting ink.

But that still leaves a question - what did he do about the color-shifting ink?

In addition, they are generally produced with enhanced security features, including watermarks, security thread, color-shifting ink, and special bond paper.

The handiest way of spotting a counterfeit $50 or $100 bill is the color-shifting ink of the bottom right number.

Other countries followed, purchasing color-shifting inks of different colors for their own currency.

This is especially true of the black ink and the color-shifting ink.

Two places on the face of the bill contain sparkly, color-shifting ink:

The $5 bill, however, does not feature color-shifting ink like all the other denominations.