New technique identifies counterfeit collectible stamps
By Ben Coxworth
August 16, 2013
Here’s good news for all you philatelists out there – scientists have discovered an easier new way of detecting counterfeit rare stamps. Unlike some existing methods, it doesn’t require the destruction of any part of the stamp, and can be done quickly by anyone who has access to the necessary equipment.
First of all, it’s probably news to some people that there even are such thing as counterfeit stamps. Considering that some of the world’s most valuable stamps are worth several million dollars, however, it becomes easy to see why some unscrupulous folks would look into cranking out their own convincing copies.
Traditionally, the authenticity of rare stamps has been verified by destructively analyzing individual components of them (such as a sample of the ink), or through inspections performed by highly sought-after experts.
A team from Italy’s Università del Salento instead tried using a technique known as infrared spectroscopy. Putting it simply, IR spectroscopy involves subjecting a sample of material to a beam of infrared light, and studying how that material absorbs the light. Because known molecules absorb IR light at specific frequencies, the presence of those molecules can be inferred when light transmitted at that frequency is absorbed.
The researchers took a wide variety of Italian stamps (dating as far back as 1850) that were known to be authentic, and used the technique to produce a profile of each stamp’s components – these components included its paper fibers, fillers, inks, adhesives and coatings. Other stamps were then also analyzed, to see if they matched up with the profiles of the authentic stamps that they claimed to be. Out of 180 stamps tested, the IR spectroscopy technique detected two fakes.
According to the scientists, the process is simple, precise and immediate. A paper on their research was recently published in the journal Analytical Chemistry.
Source: American Chemical Society