Film photos can actually be retouched to deceive the whole world...

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In today's world of digital photography, photo editing software and AI, it is so easy to adjust the color, beautify or even use Photoshop to synthesize a photo. However, more than a hundred years ago, when photography technology was just emerging and there were no digital cameras or Photoshop, there were dozens of old black-and-white photos that shocked the world. In the end, people found that they were "Photoshopped"!

Can old photos be beautified to make them look real?

The left picture is before modification, and the right picture is after modification. Image source: Reference [1]

Have you seen the photo on the right? This is a portrait of the famous former US President Abraham Lincoln when he was campaigning. Lincoln is leaning against a table, looking relaxed, gentlemanly, and perfect. However, this is actually a fake photo - someone "Photoshopped" the head of politician John Caldwell Calhoun and spliced ​​Lincoln's head on it.

The left picture is after modification, and the right picture is before modification. Image source: Reference [1]

Benito Mussolini, the founder of fascism, removed the horse trainer from the original photo, allegedly to make him appear more heroic.

The left picture is after modification, and the right picture is before modification. Image source: Reference [1]

In 1939, King George VI of the United Kingdom and his wife Queen Elizabeth took a photo with then Canadian Prime Minister William Lyon Mackenzie King. However, when the photo was used in the campaign of the later Canadian Prime Minister, the King of England mysteriously "disappeared".

Dr. Hany Farid, an expert on image manipulation at Dartmouth College in the United States, said: "While we may think that photo manipulation is relatively new and a product of the digital age, the fact is that history is riddled with photo forgeries ." If you want to know why old photos could be post-processed and PSed at the time, you must first understand the principles of photography.

Image source: pxhere

The principle of film

Film appeared in the late 19th century. People tried to react wood pulp and acetic acid under the action of a catalyst to obtain a film material called cellulose acetate. As the film base, common films are mainly black and white negative film and color negative film . In order to make cellulose acetate sensitive to light, people coated this material with a layer of photosensitive emulsion.

Take black and white negative film as an example. When we press the shutter button, light enters the camera through the camera lens and is projected onto the photosensitive film filled with silver halide microcrystals, causing the silver halide crystals to undergo structural changes and form a latent image . The stronger the light, the more silver halide microcrystals will gather and denature.

One of the two silver halide microcrystal particles on the film is exposed to light (hν) to form a latent image (step 1). The developer is used to amplify the latent image and convert the silver halide crystals into metallic silver particles (step 2). Finally, the non-light-sensitive silver halide is removed by fixing (step 3). Image source: wiki

To turn this film into a photo, it needs to go through the steps of washing and enlarging. Washing is to develop and fix the film with latent image in the dark with developer and fixer. This can not only restore the photosensitive silver halide microcrystals into stable black metal silver particles and fix them, but also prevent the silver halide microcrystals on the film from continuing to react with photons and changing the image already shot on the film.

At this time, the part of the film that is exposed to strong light will have black metallic silver particles left, making it opaque. The silver halide microcrystals in the dark part have not changed much, and finally washed away, making it more transparent. In other words, the brightness of the film is exactly the opposite of the scene being photographed . Therefore, people are used to calling it a negative film.

How to Photoshop Film

During the negative film stage, people often use Photoshop to manually edit photos. For example, use a pencil to darken a pimple on the face, so that the pimple disappears when the photo is developed. Or use a pencil to reconstruct details such as the shadows on a person's face.

In the photo published in the Russian magazine Ogoniok, the watch on the soldier's left wrist was removed in post-processing... (The left photo is after modification). Image source: Reference [1]

Next, the washed and dried film is transferred to photographic paper using an enlarger to turn it into a photo. The principle of this step is similar to that of film development. The light emitted by the enlarger will pass through the negative and project a clear image on the photographic paper at the base. In this way, the image and color on the negative will be transferred to the photographic paper, and then the photographic paper will go through the same development and fixing steps as when processing the original film, so that the image can be presented with the correct color and light and dark.

During the enlargement process, people can remove people or objects in the photo by blocking or cutting , and then fill in the blanks with a pen to make the photo more beautiful or meet their needs.

Or you can put two negatives together to create a composite photo. This can be used in many scenarios, such as making someone who was not present appear in a group photo, or as shown below, people put two unrelated people together to make them look like acquaintances communicating privately.

Image source: Reference [1]

The principle of film

As AI develops, false images will only increase in number, and if our brains perceive these images as real and remember them, these false memories will not only distort our view of the past, but may also affect our future.

So how do you spot a fake historical photo when you come across one? Image experts point us to some straightforward methods: Try to find the largest version of the picture so you can see the details, like most AI programs still have problems with hands, you'll see people have extra fingers or look weird.

Image source: AI

Or do a reverse search on the images to find when and where they were first uploaded. If a perfect photo is reposted from an unknown media or website, then the photo is likely fake. Or use an AI detection tool like Hive Moderation , which can tell you how likely it is that an image was generated by AI.

When the false is made to appear true, the true becomes false.

References

[1]https://www.dailymail.co.uk/news/article-2107109/Iconic-Abraham-Lincoln-portrait-revealed-TWO-pictures-stitched-together.html

[2]https://observers.france24.com/en/europe/20230502-ai-historical-photos-fake-fact-check

[3]https://amateurphotographer.com/iconic-images/best-photo-hoaxes/

Planning and production

Source: Bringing Science Home (id: steamforkids)

Author: Ah Xian, editor of "Everything" magazine

Reviewer｜Editor of Skin Magazine

Editor｜Yinuo