When banknotes were first issued in Europe in 17th century,

they were crude and easily duplicated.

Some historians believe the counterfeits in circulation outnumbered real banknotes.

To make paper money harder to forge, there's been a stream of innovations -

from elaborate engraving, watermarks to security thread.

But these technologies couldn’t prevent a $900,000 swindle back in 1966 in Australia -

which is how we got plastic money.

In come the dollars, in come the cents

to replace the pounds, and the shilling and pence.

In 1966, Australia switched from pounds to decimal currency.

The country’s reserve bank issued a new range of banknotes with modern safety features -

including watermarks, woven metal thread

and raised areas thanks to being printed on Intaglio presses.

Soon though, fake ten-dollar notes that looked authentic began to appear.

In the following years, hundreds of thousands of dollars worth of Australian fake notes -

all with watermark and metal threads - passed into circulation,

undermining confidence in Australia’s new money.

It wasn’t the work of a sophisticated criminal mastermind,

but instead a shopkeeper, an artist, a photographer and a tailor.

Financed by career criminal Robert Kidd

the gang bought a colour printing press, a camera lens and some ordinary paper.

The photographer took pictures of a genuine note and a watermark drawn by the artist.

The tailor took a week’s printing training

and ran it with the shopkeeper in a garage.

The counterfeiters were soon caught,

but the authorities were alarmed by how easy they were able to copy the money.

In 1968, the then governor of the Australian central bank H.C. Coombs,

challenged a team of experts to create a more secure banknote.

A representative from camera company Kodak made the point that

if the new banknotes could be photographed

then they could also be printed and forged.

It inspired David Solomon, a polymer chemist.

He came up with a novel idea of a plastic note

after being given a business card printed on plastic by a Japanese professor.

Within a few years, Solomon’s team developed a unique polymer substrate,

which contains several film layers.

The molten polymer is forced out of a circular die in the form of a bubble.

The bubble is drawn up a tall vertical tower.

The size of this bubble and hence the film thickness

is controlled by the air pressure within the bubble.

Using polymer meant other security features could also be included.

See-through panels contain Optically Variable Devices -

holographic-style images that are hard to copy, or take a photo of.

Printed on plastic, it incorporates for the first time anywhere this Optically Variable Device

which takes on a different appearance depending on the angle at which you view it.

In 1988, the new technologies were first used in A$10 commemorative notes.

The technology has now been exported to 25 other countries.

As well as their security features, polymer banknotes are also cleaner

and they last two and a half times longer than paper notes, which offsets the increase in cost.

At the end of its lifecycle, the plastic note can be recycled to make other products.

Today plastic money is used in about 30 countries

and accounts for 3 percent of the world’s money.

In Australia, plastic notes have helped

keep counterfeiting low for decades,

especially when compared with other major currencies

like Euro.

The rate has increased in recent years though

as the criminals have caught up.

So the best solution might just be to go cashless entirely.

That would also help avoid the embarrassing spelling mistake

Australia printed on 46 million of its bills this year.