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Digital age -

In the age of the smartphone, everyone is a photographer. Many of us take photos on a daily basis, whether simply to document our lives or as part of an artistic pursuit.

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The photograph -

Of course, the whole point of a photograph is to convey a certain amount of information; they are meant, quite literally, to be a representation of the real.

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Information overload -

However, the photographs we take on our smartphones and digital cameras actually hold a lot more information than many people realize.

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Metadata -

Firstly, whenever you take a digital photograph you automatically create "metadata," which is automatically embedded and stored in the photograph itself.

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Photo metadata -

Metadata is essentially data about data. In the context of photographs, it is the information about when and where a photograph was taken, and with what type of camera.

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Risk of publication -

Many people do not realize that metadata is even there, let alone that it may become public (depending on the site) when the photograph is uploaded or posted online.

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Metadata in action -

The White House was served a harsh reminder of this fact in October 2020, when it posted two photographs of Donald Trump signing papers and reading briefs.

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Photo 1 -

The photos were intended to demonstrate that Trump was working tirelessly for the American people, despite the fact that he had just tested positive for COVID-19.

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Photo 2 -

The two pictures were taken in different rooms, and with Trump wearing a jacket in one but not the other. Nothing suspicious about that, you might think.

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Busted? -

However, the metadata showed that the photos were taken only 10 minutes apart, leading to accusations that the photos had been staged for a political message.

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The reality -

Of course, there are possible explanations for the differences between the photos, but the accusations brought on the basis of the timestamps were unwelcome to say the least.

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John McAfee -

For another high-profile incident involving metadata, we rewind to 2012 and the case of John McAfee, founder of McAfee antivirus software.

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John McAfee -

When McAfee was on the run from the Belizean authorities in Central America, Vice magazine found him and posted a picture captioned "We Are With John McAfee Right Now, Suckers.”

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John McAfee -

What they did not realize was that the location data was buried in the photo they uploaded. The authorities found out McAfee was in Guatemala, tracked him down, and detained him.

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Double-edged sword -

Metadata can be used for both good and bad. It can help law enforcement track down criminals, and it can give criminals the intel they need to commit their crimes.

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Privacy implications -

There are also privacy implications for all citizens if the authorities can track their every move by looking at the photos on their cameras and social media pages.

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It doesn't end there -

But metadata is not the only information hidden in photographs. Every photo also has a unique identifier that links it to the very camera (or smartphone) it was taken with.

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Digital cameras 101 -

Inside every digital camera is an imaging sensor composed of millions of silicon "photosites." These photosites absorb photons and eject electrons, thanks to the photoelectric effect.

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Digital cameras 101 -

The charge of the electrons ejected by the photosite is measured and converted into a digital value. This gives each photosite a single value that describes the amount of light detected.

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The problem -

That is, in a nutshell, how a photo is created. Now, the manufacturing of imaging sensors is imperfect and the dimensions of each photosite vary a tiny amount.

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The problem -

Their silicon material is also inhomogeneous. All this means that different photosites have varying sensitivity to light, independent of what is being captured.

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Digital fingerprint -

Two photos of the same object or landscape taken by two cameras of the same make and model will therefore be very slightly different.

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Digital fingerprint -

Thanks to the different photosite sensitivities each camera creates an imperceptible watermark, which acts as a sort of fingerprint that can be used to identify your camera.

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Another double-edged sword -

In the digital image forensics community, this phenomenon is known as "photo response non-uniformity." As with metadata, it can be used for good and bad.

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Helpful applications -

On the one hand, it can be used to help identify fake images. Investigators in the United States, for instance, can use a patented photo fingerprinting technique to identify manipulated images and trace them to a specific device.

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Helpful applications -

According to Jessica Fridrich of Binghamton University, this technology may also help us in the future to identify AI-generated so-called "deep-fakes."

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Harmful applications -

On the other hand, this technology could put individuals who rely on anonymity for their safety, such as photojournalists and whistleblowers, at risk.

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In conclusion -

Whatever your stance on the moral and ethical questions, it is worth remembering that when you upload a picture to Insta it contains a lot more information than you might think!

Sources: (BBC)

See also: Celebrities who are also great photographers

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