Asymmetrical Serial Numbers
Used on:
• Ship $2 (purple) and $10000
• Portrait series all denominations
• All commemorative notes, except 1990 SG25 $50
Asymmetrical serial numbers are serial numbers where the digits gradually increase in size from one end to the other. This uneven look, applied to both the horizontally and vertically arranged numbers, is a security feature. It makes the numbers harder to counterfeit using normal printing methods, because the size change follows a set pattern that is not easy to fake. The digits need to be scaled and aligned very precisely, which is difficult without specialised equipment.
Asymmetrical serial numbers first appeared in Singapore on the Ship series $2 purple note and $10000 note. On both notes, the vertical and horizontal serial numbers showed digits that grew larger with each digit. This later became a standard feature in the Portrait series, where the serial numbers of all denominations used this design. Asymmetrical serial numbers is also used in all of Singapore’s commemorative notes except the 1990 SG25 $50 note.
