Hey Paul, your piece on how to spot an autopen signature led me to question my own collection, how can I tell if my artworks are forged? - B. Chess, NY

It's a rather complicated business identifying forged artworks, and one that I'm not overly well versed in, but I'm sure I can shed some light.

I've known people duped by knock-off art over the years and I'll say the same to you as I told them: provenance is everything. Whether a respected auction house or a provincial dealer, all sellers of fine art use the ownership history of a piece to ascertain its authenticity.

Any respectable seller should be able to tell you where they first acquired the piece, and through this you can normally trace the work back to its creation. However, this is truer of high-end art than the lower end of the market, where the movement of the pieces is less likely to have been recorded.

Beware of art that has just been "discovered". Although it can be tempting to place a bid on a piece that no-one has seen before, the complete lack of knowledge surrounding the work can sometimes mean it has just been created. Forgers prey on the excitement created by discovered works to ensure that they never get found out.

Take, for example, the collection of forged Jackson Pollock works that were discovered by filmmaker Alex Matter in 2005. He claimed the paintings had spent years in a storage bin. Even top scholars of the artist's work believed them to be real, before further investigations revealed otherwise.

Which leads me to some of the more sophisticated techniques employed by art experts to determine authenticity. The Pollock works were revealed as fakes after being put under a microscope, which showed a pigment used that couldn't have existed in Pollock's day - a common way of identifying a real piece from a fake.

Technology such as this has gained acceptance in the art world over the past few years and is being used more and more, as there is no need to damage the art to study a sample. This ensures that art experts are getting better at authenticating works, but the technology does come at a cost.

In summation, if you are genuinely concerned about your art, take it to an expert for a proper valuation. While this isn't a fool-proof solution, it can certainly help put your mind at ease when it comes to your investments. Art forgeries are far more common than one might think - the FBI estimates that $6bn a year is spent on forged or stolen art in the US alone!

Paul Fraser.