A new variety of Singapore’s 10-dollar note was released in January 2012, carrying the symbol of one diamond on the reverse (above the word Sports). The first prefix for this variety is likely to be 4BA. For previous varieties of the $10 polymer banknotes, the first observed prefixes were 2BA and 3BA respectively. This is due to the fact that 2AA and 3AA were one of the prefixes used in the 2004 version.

The notes were available at some branches, while other branches carried the previous $10 note variety with two triangles. A few weeks ago, the $1000 note with one diamond was found in circulation.

Symbols printed on the reverse of the notes were introduced back in 2008 as a new security feature used for authentication purposes by MAS. Despite the lack of information, a different symbol was used for each batch of notes. Based on the observations from the serial number, the symbols may either represent the print run number or the year of printing. It is also understood that there may be other symbols used, including circles and stars.

Most denominations showed the same pattern in the sequence of symbols. The earliest batches of such notes contained no symbol. From 2008, banknotes were first imprinted with one square, followed by two squares, one triangle, two triangles and one diamond.

This variety still carries the signature of then Chairman of the Monetary Authority of Singapore, Goh Chok Tong. On 21 May 2011, Deputy Prime Minister Tharman Shanmugaratnam was appointed the new Chairman of the Monetary Authority of Singapore.

Singapore $1000 banknotes with the 3AA prefix has been found in circulation, carrying the one diamond symbol on the reverse (above the word Government).

It carries the signature of Emeritus Senior Minister Goh Chok Tong, the previous Chairman of the Monetary Authority of Singapore, suggesting that the banknotes were printed before 21 May 2011. Future banknotes will be issued with the signature of MAS Chairman Deputy Prime Minister Tharman Shanmugaratnam.

The colour is more vivid on the 3AA series, as printing technology continues to improve. Such colour improvements were also observed on the latest $100 notes. On the reverse, different tints are used for the space below the arches. We compare it with an earlier variety of the $1000 note with two triangles (right).

Now, does the $1000 1AA series exist? If it does, is the symbol is a square dot (based on the pattern for other denominations)?

Scans by Mr Bin Hee Jum

In a recent auction by Mavin International on 23 July 2011, the Singapore $2 note with two triangles was revealed. However, this variety is only available as an uncut sheet of three. Each uncut sheet contains prefixes 4EQ/4FQ/4GQ or 4HK/4JK/4KK.

The banknote still bears the signature of the previous Chairman of MAS, Emeritus Senior Minister Goh Chok Tong, instead of the current Chairman, Deputy Prime Minister Tharman Shanmugaratnam. It suggests that the note was printed before the appointment date of 21 May 2011. Banknotes signed by the latter will be expected as early as January 2012.

Also, the Singapore $5 note with one square was available as an uncut sheet of three at the auction. These notes had a prefix of 3AA. The Monetary Authority of Singapore (MAS) has often made such uncut sheets available through auction only.

Scans by Vincent Tan

Placing a banknote under ultraviolet light may reveal some interesting security features. To illustrate this, we have chosen four banknotes from different countries.

From top: Peru 5000 Intis (1988), Singapore 100 Dollars (2009), Malaysia 2 Ringgit (1996), South Korea 10000 Won (2007)

The most commonly used feature is random flecks which glow brightly under ultraviolet light. These flecks cannot be seen under ordinary light and are often incorporated on both sides of the note. In order to provide a greater contrast, such notes are often printed on security paper which does not reflect ultraviolet light. For example, the 5000 Intis (1988) note from Peru and the 2 Ringgit (1996) note from Malaysia are sprinkled generously with fluorescent green and blue flecks.

Fluorescent security features can be also incorporated with other features on the banknote. On the 100 Dollar (2009) note from Singapore, the latent image bearing the MAS logo fluoresces under ultraviolet light. However, this wavy-shaped feature was not adopted by the polymer banknotes to make way for the island-shaped security thread. A security thread on the right-hand edge of the 10000 Won (2007) note from Korea gives a slight glow when placed under ultraviolet light.

Fluorescent pigment can also be used to print detailed graphics on the banknotes. The denomination is printed vertically across the 5000 Intis note, while numerals are printed in the middle of the Singapore $100 note. For example, putting a £20 (2007) note under ultraviolet light reveals a bright red and green figure 20. The serial numbers and seal on Singapore banknotes are printed with fluorescent ink.

Sometimes, these fluorescent features can be seen without using an ultraviolet lamp. For example, the numerals in the middle of Singapore’s Portrait Series of banknotes are large enough to be seen using by holding it next to the window, by means of ultraviolet rays from sunlight.

Today, many countries make use of such security features to deter counterfeiting, given that it is less easy to reproduce these features using commercially available printers. Often, these features are found on most denominations of modern banknotes. Even the 100 Trillion Dollar (2009) note from Zimbabwe has slight traces of fluorescent fibres embedded on it. Fluorescent features are found on Bank of England’s £5, £10 and £20 notes, and they are likely to be used on the Series F £50 note, to be released in late 2011.

If you wish to explore the fluorescent features of banknotes, invest in an ultraviolet lamp. This lamp should ideally emit light at 365 nanometres, which is often termed ‘black light’. For a cheaper alternative, visit a novelty store and find pens which allow one to write invisible messages which are revealed under ‘magic’ light. Here, you can purchase one at Daiso for $2.

A new variety of the $10 Singapore banknote with two triangles on the reverse was spotted in early May 2011. The two triangles were similarly printed in red, beneath the word ‘Sports’ on the bottom left corner of the note. Currently, there are a total of five varieties for the $10 note – with no symbol, one square, two squares, one triangle and two triangles, making it the denomination with the largest number of varieties at the moment.

Another denomination which has two triangles printed on it is the $1000 note.