In the 100- and 500-peso banknotes, the number printed with color-shifting ink (Optically Variable Ink, OVI) is found in the upper right-hand corner of the notes. The use of this type of ink allows the number corresponding to the denomination to change color when you tilt the note slightly. This feature is part of the intaglio printing.

		Magenta to Green
		Magenta to Green

In the 20-peso banknote, the color-shifting ink is found to the left of the body of the dove that appears on the left-hand side of the front of the note, and in the geometric pattern that is located next to the see-through window. In the case of the geometric pattern, the effect of the color-shifting ink can be seen on the front as well as the back of the note.

In the 50-peso banknotes, the color-shifting ink is found in one of the wings of the butterfly that appears to the left side of the front of the note and in the caterpillar found next to the see-through window. In the case of the caterpillar, the shift in color can be observed both on the front and on the back of the note.

On the front of the 200-peso banknotes, you can see this feature on the book with feather pen at the left-hand side. The color-shifting ink is found on the right-hand side of the book and in the feather pen. This feature is part of the intaglio printing.

On the front of the 1000-peso banknotes, you can see a stylized drawing of a church to the left-hand side. The color-shifting ink is found on the chapel and right-hand-side tower. This feature is part of the intaglio printing.

To better observe this security feature, you should hold the note face up, place it horizontally 30 centimeters away from your eyes, and turn or tilt it.