Adobe Photoshop has long been the benchmark for image retouching. Many are those who, for humorous or other reasons, have tried the art of retouching.
With the evolution of the software and especially the growing expertise of Photoshop users arises the problem ofauthenticity of images found on the Internet.
Funinformatique provides you with some techniques for knowing if an image has been edited.
1- Check consistency in the forms
It is sometimes necessary to take a step back from the observed image, this detail does not necessarily appear easily. Using a tool to isolate an area, enlarge it, and restore it to its original dimension can be helpful in this setting.
The first element to determine is compliance with the elementary laws of physics.
In this specific case, we realize that nothing is coherent, not even the movement of the tie, without even focusing on the rest of the details. Many images abuse the deformation to cause an effect of thinness, or an oversized musculature.
2- Look for the repetition of objects and shapes
Among the many features of Photoshop, cloning consists of repeating a selection of objects or part of the image. This technique is often used to erase certain imperfections, such as on the surface of the skin or to hide another object (an airplane for example by adding a cloud above or a piece of the sky).
Look for unique aspects in remarkable detail, then see if you can spot its repetition in other parts of the image. It could be someone wearing a unique hat in a crowd, a particular pattern, or repeating stars in the sky.
In the case of the image above, it is part of the crowd that has been cloned in the upper area of the photo. It is clearly a "photoshopage".
3- The inconsistencies in the image at the level of shading
Shadow is created by lighting on an object, casting a dark shape onto the surface where the object is obstructing. Photoshop is software that works on the principle of stacking layers, like paper cutouts with windows. Then come features to smooth the result and offer artificial lighting.
If anyone is new or beginner in the field of Photoshopping or editing, one of the most common mistakes you might encounter is irregularity or absence of shadows. Every object should cast a shadow, and if they aren't, the image should definitely be of a ghost.
Additionally, if an image has shadows, you must look for irregularities in the shadows. This means that an object like a stone or a box would cast a fairly defined shadow.
Based on the stated principle, shading errors are easy to spot because they are the result of an inconsistency in inserting or deleting an object layer. If you take a group photo at 17 p.m., the setting sun will cast a longer shadow than in an image taken at noon.
In this example, in addition to the shadow of the car door, the designer also forgot which way the sun was shining.
4- Checking blurs on photos and JPEG noise
The JPEG image format is ancompressed image to be able to be exchanged quickly or hosted on the Internet thanks to its low weight. The counterpart is that it loses in quality with thecompression algorithm and that by being reworked or retouched, blurry areas may appear.
Among the classic mistakes that are made in image editing, we find the " oversharpening ”Which corresponds to the forcing of the smoothness of the lines, undoubtedly to compensate for a significant loss in the definition of the image. Loss can occur when inserting a layer or a detail.
5- Color inconsistencies related to the use of the airbrush
The pictures say airbrushes produce a strange effect. The subject is often too dark or too bright, in short, it does not fit naturally into the decor. This is often the result of a makeshift edit, without the use of all Photoshop features, or a poor choice of subject.
La facial skin is certainly one of the most delicate textures to process, which makes the edits easy to spot. A good Photoshop editing cannot go completely in the direction of perfection, it must compromise with realism, even if the retouching is minimal.
6- Control the EXIF data of a photo and the geolocation
EXIF or Exchangeable image file format is a file format used for images from digital cameras. It represents theset of information that the device records when taking a photo.
This information includes the equipment used (camera / smartphone brand, model, serial number, lens, etc.). There are also GPS coordinates, especially on smartphones.
All this information can be retrieved from Windows made it “right click”-> “properties” on the image, or CTRL + click then " Properties On macOS.
If the cut is well done, but despite everything you suspect that your image is not authentic, checking this data is the most reliable way to remove the indeterminacy.
7- Use the FotoForensics online tool
FotoForensics a very well known online tool that uses an algorithm called ELA (Error Level Analysis) to identify all possible photoshopped manipulations. It gives you all the information you would need to deduce whether the image is retouched or not.
8- Use reverse image search
Finally, if you are lazy, or you don't have time to look for details in each image, you can always call on Google for check if a photo has been Photoshoped.
A reverse image search careful would not only help you get information if the image is original or not, but it will also provide you (in most cases) with the source image link.
And if you want to learn how to check if a video has been rigged, then check out this article: DeepFake: how to detect these faked videos?