Fake photos are initially difficult to spot. There are some photos that look too real, but at a closer inspection, have been tampered with multiple times. So how can we actually decipher if a photo has been edited or fabricated? It can be spotted by looking at shadows included in a photo, as Hany Farid tells BBC:
One trick he has picked up over time is to check the points of light in people’s eyes. “If you have two people standing next to each other in a photograph, then we will often see the reflection of the light source (such as the Sun or a camera flash) in their eyes,” he explains. “The location, size, and colour of this reflection tells us about the location, size, and colour of the light source. If these properties of the light source are not consistent, then the photo may be a composite.”
Another giveaway is the colour of people’s ears. “If the Sun is behind me, my ears will look red from the front because you’ll see the blood,” he says. “If the light is coming from the front, you won’t see the red in the ear.”
Take shadow, for example. If you draw a line from the edge of a shadow in a photograph, to a point on the object that is casting the shadow, you can trace that further to reveal where the light in an image is coming from. If you map out several points on a shadow, the lines should intersect.
If a photo has been tampered with, the shadows of some objects in the image may not match the light sources in the rest of the picture, says Farid. He has shown it is possible with this method to identify images that have had objects or people added after they were taken.
image via BBC