US money adds a splash of colour

The new, harder-to-counterfeit bill in reds, yellows, oranges and greens entered US circulation on Thursday.

The $10 makeover follows similar colourisation of the $20 bill in 2003 and the $50 note in 2004.

The $100 bill one of the most popular with counterfeiters - is due to be redesigned in 2007, but there are no plans to change the $1, $2 or $5 notes.

Digital counterfeiters

The US government gives its currency a new look every seven to 10 years in a bid to stay ahead of counterfeiters.

Current estimates put the rate of counterfeit $10 notes in circulation worldwide at fewer than one bill per 10,000.

But digital equipment has made it easier for criminals to produce fake currency. Since 1995, the proportion of digitally-produced counterfeit notes in circulation has grown from 1% of all fake bills detected in the US to about 54% in 2004.

The new $10 bill will give fraudsters more headaches.

It features a new portrait of Alexander Hamilton, a subtle orange background, some red highlights and a host of tiny yellow 10's printed all over the note.

The US government has embarked on a massive awareness and education campaign to ensure people are aware of the new note and its security features. Original $10 bills will remain in circulation alongside their new multi-coloured cousins.

1. Color-shifting ink: Colour changes from copper to green when note tilted - change is more pronounced on new note.
2. Watermark: Faint image appears to right of large portrait. On new note a blank oval highlights the watermark's location.
3. Security thread: Threads which glow orange under ultraviolet light were introduced in 1990.
4. Microprinting: Tiny, hard to reproduce printing is found in three places on the front of the notes. Dozens of tiny yellow 10s are printed on the reverse of the new note.
5. Serial number: Unique combination of eleven numbers and letters appears twice. The left-hand number has moved slightly to the right on the new note.