The Telltale Signs of Photo Manipulation - The Intrepid

Wednesday, November 19, 2008

The Telltale Signs of Photo Manipulation

US Army General Ann Dunwoody Photo Manipulation
Earlier today, the Associated Press (AP) accused the U.S. Department of Defense (DOD) of digitally altering a media release picture of US Army General Ann Dunwoody. In the manipulated image, the DOD altered the clarity, Dunwoody’s uniform, and the background. The DOD was aware of the changes made to the photograph, but stated that the doctored photo did not violate army media policy.

For AP, and many other news organizations, even slight changes to a photograph damage the credibility of the image. “…there's a zero-tolerance policy of adding or subtracting actual content from an image,” said Santiago Lyon, AP's director of photography. After flagging the altered photo, AP suspended the use of DOD images in its publications.

This issue raises an interesting question: How can you tell if an image has been digitally doctored?

Lighting

Often, photo manipulation involves merging one image into another. One of the easiest ways to spot a fake image is to examine the lighting. While it isn’t always apparent to the naked eye, image specialists are able to measure the brightness and light orientation in order to determine whether or not an image is a fake. Take a look at this example from Scientific American.

Ducks and Police Photo Manipulation
The light direction of the police does not match that of the ducks.

The Eyes

Another way to spot photo manipulation is to look at the eyes of the people in the photograph. Light reflects off the eye in a particular way creating small white dots called specular highlights. If the location of these specular highlights is inconsistent, it suggests doctoring.

Cloning

Cloning, or copying and pasting parts of image, is a popular method of photo manipulation. While it can be easy to spot bad clone jobs, it sometimes takes the power of a computer to scan an image for duplicated pixel regions.

Poor Fakes

While it’s hard spot good fakes, poor fakes usually have several telltale signs, such as inconsistent shadows, weird blurring, and unnecessary pixelization. (Pixelization is often used to high shoddy workmanship, like in this fake photo of a young John Kerry with Jane Fonda at anti Vietnam protest rally.)

John Kerry Jane Fonda Anti-Vietnam War Rally Fake Photo
For more information about digital forensics I recommend reading 5 Ways to Spot a Fake Photograph and How Experts Uncover Doctored Images.

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