A year ago, one photograph was everywhere: an image of Osama bin Laden, killed in a raid by US forces. But, in reality, the image was fake.
That image did not come from a camera; it came fresh from a computer. But how can we tell the difference?
At Agence France Press – AFP – in Paris, one man has developed software to help distinguish untouched photographs from their technologically doctored cousins. For a press agency, knowing the difference is vital.
The software is called Tungstène. It was designed in 2009 in response to requests from the French army and the press. It does not handle classic analogue photographs but, given a digital image, it knows exactly what’s what. A fake Iranian missile, too many funeral mourners in North Korea – Tungstène reveals every trick in the book.
It works using up to 20 filters and a giant calculator. The date the photo was originally taken and the camera used to take it are also revealed.
An optical filter, for example, shows up the diffusion of the light.
In one example, an expert deliberately added a third aeroplane to a photograph. It is a manipulation that the programme recognises immediately.
Roger Cozien, the man who wrote the programme, said: “We see the traces of turbulence behind the first two planes very clearly. We see very clearly the hot gas behind the planes and also their shape conforms to their makes. But in contrast, behind this third plane, we see there is nothing. That means that, physically, that object isn’t part of the environment. When we look closer, we realise that the third plane is the same as the one at the bottom, but copied and pasted next to it.”
Having passed all the tests, the programe is now being exported, because it is also useful for the police. Its inventor was recently invited to Switzerland by police there. Detectives were anxious to ensure that photos presented to the courts as evidence were authentic and untouched.
Swiss police spokesperson Jean-Christophe Sauterel said: “We rely increasingly on images in our work, in particular images which come from security cameras, from our own services and also those we find on social networks, where we find that some people don’t hesitate to film themselves committing crimes and then put the images online.”
In a world which is swimming in images, it is a big market. Tungstène has only just begun.