Anti-Forgery Method Traces Signatures’ Finer Points

Graphologists know that forgers can easily duplicate the shape of a signature, but that they rarely match the sequence of strokes and the pressure of the pen on the paper.

So engineers at Universita degli Studi Roma Tre in Rome developed a method, based on holographic technology, for scanning the depth of the furrows left by a pen. When one furrow crosses another, like in the center of an 8, the technique shows which stroke came first and what direction the pen was moving, said Giuseppe Schirripa Spagnolo, lead author of the study.

The shape of a person’s signature often varies, but the stroke order and writing direction almost never changes.

The researchers, whose findings were published in Tuesday’s Journal of Optics A, tested the method with various types of pens and papers and successfully identified the stroke order 91% of the time.

Although the $50,000 cost of the equipment needed means the technique is unlikely to turn up in Wal-Mart to verify credit card signatures, it could be useful to forensic investigators, Schirripa Spagnolo said.