Digital technology has made life both easier and more difficult for forgers. On the one hand, the low cost and high quality of digital printers, and the manipulative abilities of software like Adobe Photoshop, mean that computers can be used to forge certain types of art. Works on paper, especially prints (with 20th century lithographs the most-frequently forged type of art), can be extremely difficult to distinguish from careful printouts, particularly if the computer-printed print is matted and framed—few collectors insist on the frame being removed to take a closer look, and few feel the need to do so, when such prints tend to sell for "small change" in art collecting terms, a few thousand pounds perhaps, and therefore fly under the radar.

Scotland Yard's Arts and Antiques Unit once confiscated a forged Banksy, made using modern spray-paint, thick modern paper and a stencil. It was selling online for tens of thousands of pounds. As an experiment, The team attempted to reproduce the forgery, buying all of the necessary materials from a local hardware store. The total cost of the materials was about £ 6. The stencil was made simply by using Adobe Photoshop to trace an image of the Banksy painting found online, and render it the correct size to match the originals. The result was what may be the ideal object to forge: one that demonstrates just how easy some of these forgeries are to make; not necessarily requiring the craft and ingenuity of the master forgers.

The experiment proved particularly interesting because it was scientifically impossible to distinguish the forged Banksy spray-painting from an original. Materially, it was identical, made of precisely what Banksy would have used. To the eye, it was also identical – after all, these works were made by stencil. And it was an intelligent object to forge, because these works were produced in multiples: not on a massive scale, but with enough copies out there to make them relatively affordable, and not so rare as to raise suspicions, should one come on the market.

The Internet as a market for art has likewise aided fraudsters. For every high profile forger, there are dozens if not hundreds of smaller-time forgers, like the makers of the Banksy, who approach their criminal art form in a manner more basic, often without artistic skill or the elaborate mechanisms of provenance traps, but they are nevertheless remarkably successful. These are the forgers who do not make the headlines, who are not artist/magicians, but simple, pragmatic criminals. Rather than dealing with the complex and opaque organism that is the high-end art trade, they rely on small galleries, tag sales, wayward antiques markets, and that anonymous criminal playground called the Internet.

But while the digital universe has made life easier for forgers, particularly in terms of selling anonymously and forging works on paper, it has the potential to make their work more difficult, if not altogether impossible. The cost of forensic tests of objects has reduced over time, to the point at which it is not unreasonable to expect a set of forensic tests to accompany any important object that one considers buying. It is largely out of habit, and the inertia of tradition, that the art trade still relies first on connoisseurship and the opinion of experts. It need not be this way, and any buyer serious about protecting his investment would do well to insist on forensic tests (which reputable dealers and auction houses would do well to supply automatically for works valued, say, to at least six figures). By regularly insisting on forensic tests, more casual forgers might be dissuaded from testing the market, if they know that a battery of scientific tests inevitably awaits them, which they must defeat. For my book, The Art of Forgery, I examined over one-hundred forgers, and included around sixty in the book—only one of them regularly created forgeries that would fool forensic testing. The rest didn't bother, confident that, if their creations looked good enough, and they had come up with a sufficiently compelling story about how the object was found (providing it with a fake "provenance," or ownership history suggesting that the object was authentic and had been around for decades if not centuries), then no one would bother to test the objects forensically.

Elaborate, hi-tech approaches to examining art have been available for years and are constantly improving, but they tend to be used infrequently, and mostly in conservation efforts. Engineers like Maurizio Seracini look to solve art historical mysteries through science, for instance using infra-red spectrometry to look behind the surface of famous paintings like Leonardo da Vinci's Adoration of the Magi, where it was discovered that someone, hundreds of years ago, had painted over a detail by Leonardo of a church being built out of the ruins of a pagan temple—a Renaissance nod to the fact that Christianity is largely based on pre-existing pagan religion. This line of thinking would have been considered heretical in Leonardo's time, and so someone painted over that little detail, either in outrage or to protect Leonardo's reputation, and it was only uncovered through digital investigation. Seracini likewise unveiled the fact that Raphael's Lady with a Unicorn was not originally painted with a unicorn at all. Raphael's original had no pet in the lady's lap. Someone later added a lap dog cradled in her arm, and someone still later added a horn to the lap dog to transform it into a unicorn. Art historians studying the painting for centuries have thought that the unicorn was an indication that the lady in the portrait was a virgin, for legend has it that only virgins can approach a unicorn without it fleeing. All of the careful iconographic analysis was undone, and the painting must be reconsidered, thanks to this discovery.

Conservation/technology firms like Factum Arte employ elaborate two-and-three-dimensional scanning systems to provide non-contact image recordings of artworks. They have developed technological innovations to deal with specific problems that conservators might encounter, for instance making a scanner that can capture images from delicate rare books, when the books are open less than 90 degrees, and a three-dimensional scanner that captured the entirety of Tutankhamun's tomb in Egypt. Scans of sufficient quality preserve art that may physically deteriorate, and make it accessible to students and enthusiasts, who cannot necessarily travel to see the works in person. They can also reveal clues that were never before noted, as in the discovery of a laughing figure in the background of Jan van Eyck's Adoration of the Mystic Lamb, perhaps meant to be Satan, which is difficult to see with the naked eye, and which appeared not to have been noted by centuries of art historians. The way the painting is displayed, in an over-sized protective glass case, means that one cannot physically get close enough to see this figure in detail. But when the Getty Conservation Institute began a restoration of the altarpiece, it produced a billion-pixel image available online which led to this discovery. This project also includes infra-red, ultra-violet, and x-ray images of every panel of the altarpiece.

Factum Are takes their scanning service a step further and employs specialized printers alongside hands-on artists, to reproduce what has been scanned for use in museum exhibitions. These projects include creating pinpoint accurate reproductions of relief sculptures, including the entire eastern end of the throne room of Ashurnasirlpal II, based on an original at the British Museum; a full-size scan and reproduction of Veronese's colossal painting, Wedding at Cana; a facsimile of an entire room in the Tomb of Thutmose III; and a gilded bronze lion, made based on a lead copy that had stood for centuries in place of the original, which was lost in a 1651 fire at the Alcazar in Madrid. These projects are labelled as facsimiles, and are on a grand (and expensive) scale, prepared in collaboration with national ministries of culture and museums. But one can see how advances in scanning and printing, in two- and three-dimensions, could be used, in the wrong hands, to forge and deceive.

There is new digital technology available that could make for a forger-proof system, but it would need to be adapted broadly in order to do so. A team led by Dutch engineer and conservator, Dr Bill Wei, of the Netherlands Institute of Cultural Heritage, developed a system for "art fingerprinting," a means of uniquely identifying an object, which protects it against being swapped in for a forgery (as in the case of the Matisse Odalisque) and allows you to identify the object as your own, if it is ever stolen and recovered. Called Fing-Art-Printing, the system uses an extremely powerful digital camera to take a picture of a miniscule section of an object, as small as a 3.5mm square. The location of the photograph is known only to the technician who took it, and the object's owner. The photograph is then processed through software that measures tribology, the roughness of the photographed surface, down to one micron (one one-thousandth of a millimeter). Though color might change over time, roughness is less likely to alter, and so matching the rough-to-smooth ratio of an object's surface is the most reliable and consistent means of identifying it uniquely. The technology is so precise that it can map textures even in surfaces that seem not to have any visible texture at all, such as glazed ceramics, silver-gelatin photographic prints or even bullets.

The tribology is translated into a color map (in which blue is used for low, smooth sections and red for high, rough ones), and software can compare this to another photograph taken using the same technology. This art fingerprinting is non-destructive and non-contact, therefore appeals to conservators, and it is also inexpensive, requiring only the software, the camera, and a mechanical arm to position the camera precisely—it could certainly be a staple of any significant museum's conservation study.

There is no forger on earth who would be able to reproduce, down to one micron, the texture of an original, even if they knew the millimetres-wide spot photographed for testing. The problem is that someone would first need to notice that something looked odd about a possible forgery, in order to think to have it tested. While digital technology has the capability to defeat forgers it is, at the end of the day, down to a fallible person, an expert noting that something is off, in order to prompt a closer look.

Standardized forensic testing, the strategic use of powerful new digital imaging technology and the independent testing of the provenance attached to an object could well bring about an end to high-end forgeries. It is up to buyers, collectively, to insist upon such services, and perhaps pay for them out of pocket, for the art trade is not likely to volunteer.