Security Feature - Fluorescent Printing

Ever wondered what cashiers are up to when they hold your banknotes under a money detector? You know, it's that device that emits some sort of dark purple light. It's the same kind of light that attracts innocent insects towards bug zappers.

Alright, your cashier is just checking if your money is fake or not. If placed under the money detector, some parts of the banknote would normally glow and reveal interesting marks. The marks are called fluorescent prints and they "fluoresce" or glow when exposed to UV light.

The money detector holds a special bulb called the UV lamp or black light. It emits ultraviolet light which causes fluorescent dyes on the banknote to light up. Fluorescent marks usually portray the denomination of the banknote and is located off-center to the left of the portraits. The dye is also incorporated in some of the serial numbers and security fibers. This causes them to glow as well.

Fluorescent printing is not entirely new. In fact, Bagong Lipunan bills already had them. Counterfeiters have been known to replicate fluorescent printing into fake bills. thus, it is not an assurance that your money is authentic.

Security Feature - Optically Variable Ink

Optically variable inks (OVI) are very expensive inks applied on banknotes as a security feature. So far, only the 1000 peso bills have this. There are two versions of OVI printing on the 1000 peso banknotes. The image above shows the newer 'improved' version on top of the older one. The former has more coverage and its color varies better. This is an excellent security feature because counterfeiters will need a lot of effort and money to replicate it.

So why are they called optically variable inks? Tiny flakes of color-shifting film are incorporated in the intaglio ink. Thus, prints of OVI change color when viewed from different angles. The pictures below show how the 1000 figure changes from green...

to blue... Or does it?