By Cressida Smart
Brought to life in films such as How to Steal a Million and The Thomas Crown Affair (1999), art forgery has been around since the beginning of time. The ancient Romans crafted thousands of copies of Greek sculptures, ancient China is noted for its wide variety of forgeries and modern art has seen more than its share of falsified work. Some forgeries are innocent enough, usually created by students copying a master, but others were created with the sole purpose of tricking an unsuspecting public into thinking they were the real deal. There are forgers that are so good at what they do that it’s virtually impossible to tell the difference between the original and the copy – leading to many museums, investors and galleries putting millions into complete fakes. With this in mind, it is vital therefore, to establish the authenticity of a work through examination.
Some forgers have used artistic methods inconsistent with those of the original artists, such as incorrect characteristic brushwork, perspective, preferred themes or techniques, or have used colours that were not available during the artist’s lifetime to create the painting. Others have dipped pieces in chemicals to “age” them and some have even tried to imitate worm marks by drilling holes into objects. While attempting to authenticate artwork, experts will also determine the piece’s provenance. If the item has no paper trail, it is more likely to be a forgery.
One of the most common methods is forensic examination used in Portrait of a Woman, attributed to Goya (1746-1828). Conventional X-ray is used to detect earlier work present under the surface of a painting. Often artists will legitimately re-use their own canvasses, but if the painting on top is supposed to be from the 17th century, but the one underneath shows people in 19th century dress, the scientist will assume the top painting is not authentic. Furthermore, x-rays can be used to view inside an object to determine if the object has been altered or repaired. When x-ray images were taken of Portrait of a Woman in 1954, it revealed a portrait of another woman, circa 1790, beneath the surface. X-ray diffraction analysis, which analyses the make up of the paint revealed the presence of zinc white paint, invented after Goya’s death. Further analysis revealed that the surface paint was modern and had been applied so as not to obscure the craquelure of the original. After analysis, the conservators left the work as it is seen now, with portions of old and new visible, to illustrate the intricacies of art forgery, and the inherent difficulty of detecting it.
Other forensic methods include including carbon dating which measures the age of an object up to 10,000 years old and x-ray fluorescence which bathes the object with radiation causing it to emit X-rays. This reveals if the metals in a metal sculpture or if the composition of pigments is too pure, or newer than their supposed age; it can also reveal the artist’s fingerprints.
As expected, with the speed in which technology has developed over the last ten years, digital examinations are often used. These include statistical analysis of digital images of paintings, whereby a picture is broken down into a collection of more basic images called sub-bands. These sub-bands are analysed to determine textures, assigning a frequency to each sub-band. The broad strokes of a surface such as a blue sky would show up as mostly low frequency sub-bands whereas the fine strokes in blades of grass would produce high frequency sub-bands. Recently, a group of 13 drawings attributed to Pieter Brueghel the Elder was tested using the wavelet decomposition method. Five of the drawings were known to be imitations. The analysis was able to correctly identify the five forged paintings.
One of the most famous recent battles over authentication includes La Bella Principessa attributed to Leonardo da Vinci. Depending on whom you ask, this painting is either a priceless masterpiece by Leonardo da Vinci or a highly skilled copy worth just $20,000. The authenticity of this work has been a hotly contested topic since 2008 when art dealer, Peter Silverman, claimed he discovered it in the drawer of a Parisian friend’s home. The story, while romantic in nature, was untrue seeing as how the work had been auctioned and sold to Silverman several years previously. Despite initial excitement about the work, as new ones by Leonardo rarely come on the market, the story might have ended there. However, several noted art historians and art experts came to support the theory that it might not be that of da Vinci. These experts claim to have science on their side, but so do their detractors and both have produced compelling evidence in support of their positions. The debate over the authenticity of this work could rage on indefinitely, but one thing is sure, whether the work was done by da Vinci or another artist, it’s a beautiful and skillfully drawn portrait. Its value has leapt from the approximate $20,000 purchase price to a Leonardo-worthy $150 million. Keep in mind, though, that the high figure is contingent on unanimous attribution by the experts, and their opinions remain divided.
Whilst authentication methods are improving, so are the techniques employed by the forgers themselves. Where once art dealers and auction houses were overly eager, by accepting forgeries as genuine to turn a neat profit, increasing time and effort is now made to establish provenance and authenticity where there is doubt.