Can you tell if a picture is fake?

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Internet is already full of digital images and more is added every day. Digital pictures have become a cheap way for journalists to tell a story and ordinary people upload tons of them to social media. It’s quicker and easier to snap a shot and upload than to describe where you are and what the place looks like.

Photographs have always been seen as some kind of proof. Like a captured piece of reality. We are however aware of the fact that photographs can be manipulated. Digital image processing has revolutionized this area and brought amazing new techniques to us. But image manipulation has actually been a known technique since photography was invented. It is amazing to see what a skilled person can do to traditional images in the darkroom. Not to mention the fact that you can lie a lot just by taking the picture in a certain way.

This article is about our relationship to the digital images on the net. There’s a lot of manipulated pictures out there, but are you able to recognize a fake? And are you even alert and aware that the picture may not be the full truth? We are all confronted with many pictures a day that aren’t completely real. Objects may be added or removed, or heavy retouching has been used to make models look better. Here’s some concrete hints about how to tell the fakes from the real ones.

  • In what context is the picture presented? Image manipulation is the norm in some contexts, like product and fashion photography, and some kinds of artistic photo. News agencies and nature photographers on the other hand have strict ethical rules against manipulation. First think about if manipulation is to be expected and if it should be accepted. Does it matter if the photo isn’t real?
  • Is the image realistic overall? Some manipulated images are so surrealistic that you can dismiss them as unreal at once, even if they are very well done technically. Ask yourself; can this be real? See the illustration to this article for an example.
  • Do you have access to several shots from the same scene? Are there discrepancies between them?
  • Are light and shadows similar between objects in the picture? Pay attention to which side is lighter, how hard the light seem to be and how the objects cast shadows. Needless to say, objects close to each other get the same light in real life. If they are illuminated differently, they may originate from different photos. Also pay attention to the environment. From what direction is the light supposed to come?
  • Is the perspective right? Getting this right is always a challenge when combining objects from different pictures. Just look at the shot and trust your gut feeling. Pictures with minor perspective errors do often feel wrong even if you can’t tell what the problem is.
  • Does the objects’ edges look right? A lot of work may go into the edges when putting something in front of a new background. They often give away the fake if they are done sloppily or with lacking skills. Pay special attention to people’s hair as that is hard to mask.
  • Image manipulation often requires filling areas to replace removed objects. Patterns that repeat in an unnatural way is a sure sign of sloppy cloning. Cloning can also be used to multiply an object, but several identical object do rarely look exactly identical in a real photo due to differences in perspective and lighting. It’s fishy if they look identical in a picture.
  • Is the color consistent? Do different parts of a human’s body have the same skin color? An object’s apparent color depends very much of the illumination’s color temperature. Do the different objects have a consistent color cast?
  • All digital capture devices leave some kind of structure in the picture. Most notable is the noise produced by digital cameras. You can check that this structure is constant over the whole picture if you have access to a fairly hi-resolution image. It’s futile to try this on small images from on-line news sites.
  • Metadata is data hidden inside the image files. One important piece of data is the software used to save the file. A camera model name would indicate no manipulation at all. Workflow programs like Adobe Lightroom and Apple Aperture are typically used to do moderate adjustments of images, but no real manipulation. The image may be heavily manipulated if it is saved by Photoshop. But this does on the other hand prove nothing as you can do minor adjustments is Photoshop too. Also remember that this data may be lacking or even forged.
  • Even if a picture is totally genuine, it may be misleading if presented in the wrong context. Like someone using a picture of somebody else for a dating site profile. Here Google Image search comes in handy. Click on the camera to the right in the search field to open “Search by image”. Upload a copy of the image or paste in a link to it on the net. Google will search for images that look the same regardless of what context they are published in. This can often reveal that the image was found on the net rather than taken by someone who has posted it as his own.

That’s a quick list of things that help you spot the fakes. Using these hints require some training, but you will soon start seeing the manipulations if you keep them in mind when looking at images. But is it possible to make a perfect fake that is undetectable? Yes, especially if a skilled artist can work on a high resolution image and the result is scaled down to be published on the web. That down-sampling can hide the signs of manipulation effectively and make the fake practically undetectable for laymen. Scientific analysis methods are more capable, but they are not available to us mortals. And they may also fail to detect good fakes.

So the moral of the story is really that a photo shouldn’t be trusted too much unless its background is known and we know what ethical principles the photographer and publisher adhere to. News agencies typically pay attention to this and promise us authentic news pictures. These pictures are typically trustworthy, even if scandals do occur.

Safe surfing,Micke

PS. This funny video is one of my favorites on YouTube.

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