Cataloguing the ‘fingerprints’ of our cultural heritage

Art gallery
There are sometimes suspicions when a stolen painting is returned to its owner. People are not always convinced that they have been given the genuine article. However, if a stolen painting is returned and it has been recorded in our database, a simple test can allay any concerns that the owner might have.
Dr Bill Wei
Earlier this week, thieves took artwork worth millions of euros from the Kunsthal Musuem in Rotterdam. Dutch police revealed that paintings by the artists Pablo Picasso, Lucian Freud and Henri Matisse were amongst the burglars’ haul.

Sadly, there is only so much that can be done to prevent situations like this from occurring. No matter how robust the security measures taken by galleries and museums, criminals will attempt to steal pieces of our shared cultural heritage, and occasionally they will succeed. However, as retired FBI agent Robert Whitman told, art thieves tend to struggle when trying to sell their illegally-acquired artefacts, and stolen pieces often end up back in the hands of authorities. It is at this point that problems concerning verification can arise. How can an owner be sure that the returned artwork is identical to that which was taken in the first place?

As part of the European Commission’s Sixth Framework Programme (FP6), scientists working on the FINGaRtPRINT project believe that their system offers the ideal solution. The team has developed a tool capable of obtaining a unique signature from any surface. Moreover, the technique requires absolutely no contact with the artefact and this signature cannot be forged.

I spoke to project coordinator Dr Bill Wei from the Netherlands Institute for Cultural Heritage to find out more about the philosophy behind FINGaRtPRINT. I began by asking Dr Wei how the system actually works.

"In engineering, you can measure roughness," he explained. "Ball bearings, axles, tables – everything has a roughness. 30 or 40 years ago, you might have measured roughness using a phonograph needle, but nowadays we can do this with a confocal light microscope. If you look through a microscope at a rough surface, you can’t focus on all of it at once. You have to turn a knob to make the lens move up and down and this enables you to focus on certain levels. It’s the same principal that National Geographic uses when mapping mountains. Geographers create topographic maps in which different colours denote different heights. This is a way of representing real numbers.

"When you focus at different depths, you are essentially conducting height measurements; the lens of your microscope is moving up and down. Simply put, confocal light microscopy measures every depth within a surface and translates these depths into numbers. The result of this process is a contour map similar to those produced by National Geographic. This map is completely unique to the object that you are cataloguing. It is measured on a scale of less than a thousandth of a millimetre. Imagine that you have two mass-produced, glazed coffee cups of the same type. If you were to measure a square centimetre on both cups at exactly the same position, you would never get the same reading. Tiny bubbles would be present within their glazes and it would be impossible to position all of those bubbles in the right place."

One of the great advantages of this system is its non-contact nature. Preserving artwork for posterity is an important responsibility of the global art community, and FINGaRtPRINT is in keeping with the ethics of conservation.

"On the whole, works of art are unique," said Dr Wei. "If you are dealing with paintings, for example, there is only one original. Part of conservation ethics is trying to have as little contact with the object as possible. Even a fingerprint can react unfavourably with a surface. Obviously, if you drag a needle across an work of art, you are scratching it. In the absence of a non-contact technique, you might have to use a barcode or a radio-frequency identification (RFID) chip. Both of these methods involve actually attaching something to the object in question."

Unfortunately for the curators of the Kunsthal Musuem, the FINGaRtPRINT system is not yet in operation. The ability to obtain signatures that cannot be forged will no doubt be welcomed by the art community.

"There are sometimes suspicions when a stolen painting is returned to its owner," Dr Wei explained. "People are not always convinced that they have been given the genuine article. However, if a stolen painting is returned and it has been recorded in our database, a simple test can allay any concerns that the owner might have. You don’t have to scan the entire painting; all you need is a couple of square millimetres. The system has been designed to locate exactly the same place on a painting that was scanned initially. If you compare the signature of a piece that has been returned with that stored on the database, you can tell whether or not the artefact is the same."

During our conversation, Dr Wei was careful to correct me on my use of the term ‘authenticity’, when describing the capabilities of his system. FINGaRtPRINT, he emphasised, is simply an effective tool for establishing an article’s identity.

"I would hesitate to use the word authenticity," he said. "It is not my place to say whether or not a work of art is authentic. What I can offer is a definite answer as to whether the piece that you have brought to me today is the same as the one that I originally catalogued.

"I should mention that there are also potential applications within the field of illegal art trafficking," continued Dr Wei. "You sometimes hear about scandals in which artefacts are illegally transported from a country such as Italy or Afghanistan to other museums around the world. If we can take FINGaRtPRINT into the field – and this is our ultimate goal – we can help to prevent this from happening. We cannot prevent people from stealing things but we could help to control the sale of these things. In order to sell a work of art at present, you need documentation and photographs. The problem is that these are all forgeable. However, if a unique digital signature was required in order to sell or buy an object, illegal trade would become much more difficult."

Dr Wei and his team are now concentrating on securing further investment and reducing the amount of time needed to catalogue an artefact. If their system is adopted by the world’s art community, art forgery could well become a thing of the past.



Could this apply to other senses? I noticed that I can often distinguish a smell just by holding an object even if I can't see it or know what it is. many years ago I used to work in a candle store and stocking shelves I wouldn't have to look at the candle I could reach out touch it and put the candle on the shelf because I could smell it with my hands.

Commented CJ on
Synaesthesia and savant syndrome: are we all superhuman? Ltd, Ebenezer House, Ryecroft, Newcastle-under-Lyme, Staffordshire ST5 2UB
Tel: +44 (0)1782 630200, Fax: +44 (0)1782 625533,
Registered in England and Wales  Co. Reg No. 4521155   Vat Reg No. 902 1814 62