Digital Watermarking

This technology has been around for a while now, but as technology is changing, it could soon be applied to postage stamps. The reliability and accuracy of this technique, if applied to stamps and currency, could in effect, wipe out all forms of forgery.

In visible watermarking, the information is normally visible in image. For stamps, the watermark will be seen when held up to the light, or through watermark detecting machines. Typically, the information is text or a logo which identifies the origin of the item. The more complex the design, the harder it is to forge.

In invisible watermarking, information is added as digital data to the picture, but it cannot be perceived as such. A barcode for example is a form of a digital watermark, which is visible. But imagaine a barcode on a stamp, invisible to the naked eye, which could be read by a computer.

Using a form of microprinting invisible to the naked eye, large amounts of information could be added to an image, without the user even being aware of it. Only if the item were copied, would the missing information be noticed.

At the moment, the main application is being considered for bank notes, which could be easily scanned by banks and large retailers. The technology could then be easily ported to postage stamps, and may have some extra advantages when used with sorting technology.

A full article will be produced as soon as further details of the trials are available.

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