Can We Photograph a Thought? Victorian Experiments with the Invisible

Gabrielle Birchak/ February 10, 2026/ Modern History/ 0 comments

^{_{By Moroder, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=182551068}}

Imagine this. A person sits perfectly still. A photographic plate is pressed to their forehead and wrapped in black paper so no light can reach it. They concentrate on a single image, a bottle, a bird, a face. Minutes later, the plate is developed, and a strange shape appears, a cloudy stain, a faint outline, a mark that looks like it came from nowhere.

And in the late 1800s, some people looked at those marks and said, “There it is. A thought.”

This is not a story about people in top hats doing party tricks, although there will be plenty of room for skepticism. It is a story about how new technology can make the impossible feel suddenly reasonable, and how easily the human brain turns mystery into “evidence,” especially when a chemical plate gives us something, anything, to point at.

By the end, will find out what tools they used, why the idea felt plausible at the time, and what these experiments accidentally teach us about photography, perception, and the modern hunger to “see” what is happening inside our minds.

The Victorian appetite for invisible things

To understand why photographing a thought sounded even remotely plausible in the 1890s, we have to picture what the century had already done to ordinary human expectations.

Photography itself had arrived like a miracle. A machine could trap time. It could pin a face to paper. It could preserve a person who would be dead next year, but still staring back at you a decade later. Early photographs even looked ghostly: pale faces, long exposures, blurred movement. The medium practically invited supernatural interpretations.

At the same time, electricity had moved from laboratory novelty to public spectacle. Invisible forces were no longer purely philosophical. Telegraphy had already taught people that unseen signals could travel long distances and carry meaning. If an invisible electrical pulse could carry a message across the world, then perhaps an invisible mental pulse could leave a trace, too.

In November 1895, something happened that poured gasoline on the entire “invisible made visible” imagination: Wilhelm Röntgen produced an image using X‑rays, a “new kind of invisible light.” Suddenly, it was not just about photographing a person. These “specialists” could photograph what was inside of us, including our skeletons. We were given evidence that the camera could reveal realities our eyes could never see.

So, if the body had invisible rays, and the photographic plate could capture invisible rays, why not the mind?

Around the same period, spiritualism was wildly popular, and not only among the gullible. Then, when we couple this with devices like telegraphs, telephones, and cameras, which were beginning to reveal hidden worlds of sound and light, it wasn’t a big leap for many to imagine that photography could bridge the gap between the living and the dead.

Spirit photography had already made headlines decades earlier, including famous claims associated with photographer William Mumler. Whether fraudulent or sincere, the cultural point is that many people wanted technology to confirm what grief and hope already wanted to believe. Unfortunately, some were fraudulent, and they recognized that manipulative techniques like double exposure, where one image is laid over another, could turn an ethereal image into either a ghost or a thought.

“Psychical research” groups tried to apply experimental methods to phenomena such as telepathy, apparitions, and communication with the dead. The Society for Psychical Research was founded in London in 1882, and photography became part of this larger attempt to document the unseen.

So, the late Victorian world was full of “invisible forces” that had started to look photographable. Thought photography did not arrive in a vacuum. It was part of a culture primed to accept strange images as proof.

The theory behind it: “vital fluids” and the soul as radiation

Here is the key idea that made “photographing thoughts” feel scientific to its supporters:

They believed living organisms emitted an invisible radiation, sometimes described as a “vital fluid.” This belief did not pop out of nowhere. It was tied to older theories like Mesmer’s “animal magnetism,” and later to the concept of “Odic” forces developed by the natural philosopher Carl von Reichenbach in the mid-1800s.

In this view, the body was not just meat and bone. The nervous system, electricity, magnetism, and life itself were connected by currents that might be invisible but still physical.

And if the photographic plate was extremely sensitive, sensitive enough to record light and detail beyond human vision, then maybe it could record these “vital fluid” emissions as well.

In other words, they were trying to treat the soul as a measurable field. Which brings us to one of the central characters in this story.

^{_{Hippolyte Baraduc, The Human Soul: Its Movements, Its Lights, and the Iconography of the Fluidic Invisible (Paris: Librairie Internationale de la Pensée Nouvelle, 1913).}}

Hippolyte Baraduc and “psychicones,” or pictures of the soul

In Paris, at the end of the 19th century, a French physician named Hippolyte Baraduc claimed he could capture images of mental states and emotions directly onto photographic plates.

Baraduc presented these images in a book published in 1896: L’Âme humaine, which isoften translated and discussed in English as The Human Soul. Baraduc called the resulting images “psychicones,” meaning images or traces of the soul.

What did his “tool” look like? It was not a regular camera, at least not always.

Baraduc often used photographic plates as direct receivers, treating the plate almost like a scientific sensor. In some cases, the plate was placed against a person’s forehead. The logic was simple: reduce the distance between “the mind” and the sensitive surface.

He was not trying to take a crisp picture of a thought, like a little photograph of a bottle floating above the skull. He claimed something different: he claimed the plate recorded the radiation of emotion and psyche, which might appear as abstract traces, clouds, bursts, or veils.

One striking example, discussed in modern scholarship, involves a boy mourning a pet. Baraduc interpreted a cloud-like shape above the boy’s head as a material trace of grief.

Here is the detail that makes this fascinating, even if it could be construed as nonsense. Baraduc’s plates often looked like abstract art, and that mattered.

Because if the soul is immaterial and mysterious, then a non-mimetic, abstract mark can feel more believable than a neat little picture. According to historian Nicolas Pethes, the abstract character of these traces helped them seem convincing to contemporary audiences precisely because the soul itself was considered abstract and difficult to represent.

In other words, the weirdness was part of the persuasion.

Baraduc’s story is not just “a man was wrong.” It is the story of someone using the era’s newest credibility machine, photography, to create physical plates and prints that looked like evidence and invited interpretation as scientific proof, even when the marks could have been caused by ordinary chemicals or handling.

If you have ever seen a blurry image online and watched people argue about what it “really shows,” you already understand the dynamic.

_{^{By Louis Darget Le Volcan (Photographie fluidique de la pensée), 1902 — https://www.artnet.com/artists/louis-darget/le-volcan-photographie-fluidique-de-la-pensée-3oYPZlpDYBUHZ5RbRrIXqA2, Public Domain, https://commons.wikimedia.org/w/index.php?curid=156903186}}

Louis Darget and the dream of “thought images”

Now we turn to the version that is closer to what we usually imagine when we say “photographing thoughts.”

Louis Darget was a French professional soldier who developed an interest in spiritual photography. He tried to capture images of thoughts by pressing unexposed photographic plates to the foreheads of sitters. At the same time, they attempted to transmit images from their minds onto the plates.

That was the demo in its most dramatic form:

They took an unexposed photographic plate.
They prevented ordinary light from exposing it (often by wrapping it).
They pressed it to the forehead.
The subject would concentrate intensely on an image.
The “specialist” then developed the plate.
Then they would interpret whatever appears as the “trace” of thought.

Darget’s plates could look like stains, bursts, or vague forms. Supporters might say the image is emerging through the “vital fluid,” the energetic substance linking mind to matter. And, notably, skeptics would say that the “specialist” just made a chemical surface behave chemically.

And that is the perfect pivot to the obvious question. What was actually happening on the plates?

Even if we take the paranormal claims out, we still have a real phenomenon: photographic materials can produce images without a camera, and without a meaningful external scene.

Several mundane mechanisms could create marks on an unexposed plate, including pressure and contact artifacts. When something is pressedagainst a sensitive surface, it can leave irregular patterns. Light leaks can also create marks. Wrapping it in black paper is a nice idea until we remember how easily tiny cracks of light can creep in, especially over time. Additionally, static electricity can fog film and create branching and lightning-like patterns. Marks on an unexposed plate can also be caused by chemical contamination. This includes oils from the skin, residue from handling, moisture, or uneven development, which can create blurs, halos, and ghostly patches. Finally, marks can also be caused by heat and humidity. They often used glass gelatin dry plates that were chemically sensitive. Heat and humidity can increase chemical activity, leaving images that were foggy and blotchy.

In other words, a photographic plate is not a neutral window. It is a reactive chemical skin. And once there is any mark, human perception can take over.

We are meaning-making creatures. We see faces in clouds, animals in constellations, and patterns in randomness because pattern detection is one of the brain’s core survival skills.

For a modern parallel, think about medical imaging. When an imaging technology is new, there is a period when interpretation lags behind its capabilities. People argue over what a blurry structure “means.” They fill gaps with assumptions, and thought photography lived in that gap.

This is not a dismissal of the past as “stupid.” It is a reminder that every era has its own seductive new instruments, and that there are so many unknown factors that can be perceived as both magical and scientific.

Why this matters today: brain scans, algorithms, and the modern “mind picture.”

Here is the twist that makes this more than a historical curiosity. We still want to photograph thoughts. However, we do it with different tools and more careful statistics.

Today, researchers use EEG, fMRI, and other methods to correlate patterns of brain activity with perception, attention, and, at times, approximate mental imagery. These methods do not produce a literal photograph of one’s thought. Conversely, they do create visual representations of brain activity that can feel eerily like mind-reading to the public.

And the same risks remain. We can overinterpret noisy signals, confuse correlation with certainty, and forget how much interpretation lies between data and conclusion.

The Victorian-thought photographers remind us that a picture can feel like proof even when it is a chemical accident plus a persuasive story.

At the same time, they also remind us of something more generous: that curiosity drives people to attempt the impossible. Sometimes those attempts produce nonsense. Sometimes they create new art. Sometimes they produce new science indirectly, by forcing better methods and stricter controls.

Pethes notes that the influence of these “soul photographs” was ultimately more substantial in art than in science, with their abstract forms resonating with emerging modernist aesthetics.

So yes, in a strange way, trying to photograph the soul helped normalize abstraction as a serious visual language.

What to remember from the thought-photography craze

Here are three takeaways.

First, the late Victorian period was a perfect storm of new media, public spectacle, and genuine scientific discovery that made “invisible forces” feel newly recordable, especially after X‑rays.

Second, people like Hippolyte Baraduc and Louis Darget were not using magic cameras. They often used photographic plates as sensors, then interpreted the resulting marks as evidence of mind, emotion, or soul.

Third, this is a story about interpretation. The plate gives us a trace, and the human mind rushes in to complete it. That impulse has never gone away. It is why science needs controls, replication, and humility, especially when the results look exciting.

It is also a reminder to keep going after the first intriguing result, especially when it feels like a breakthrough. Science asks us to dig deeper, test simpler explanations first, and then ask whether the effect survives when we tighten the method, reduce bias, and repeat the process under clearer conditions. If it disappears, that is not failure. It is information, and it points us toward what was really causing the result. If it holds up, then something genuinely new may be waiting on the other side of careful replication.

At its best, that process does not crush curiosity. It shelters it from wishful thinking and from the urge to stop at the first thrilling story. It lets wonder breathe, but it asks wonder to walk. It turns a spark into a lantern, and then it holds that light steady long enough to see what is actually there. In that steady light, imagination is not dismissed. It is science based discipline, when explored deeper, becomes the beginning of knowledge.

Until next time, carpe diem!

Math! Science! History!™

with Gabrielle Birchak