Uploaded February 2026 | Updated September 2026, 2 weeks ago
A camera was not always needed to “capture” a thought. In the late Victorian era, a few experimenters pressed photographic plates to foreheads and claimed the developed marks were images of the mind.
In this episode of Math! Science! History!, we trace the strange rise of “thought photography,” why it sounded plausible in an age of new invisible forces, and what these experiments reveal about technology, interpretation, and scientific method.
What Develops in the Dark
What you’ll learn in this episode:
1. Who tried to photograph thoughts - How Hippolyte Baraduc and Louis Darget used photographic plates as instruments, then read the resulting traces as evidence of emotion, soul, or mental imagery.
2. Why the idea felt scientific at the time - How late-19th-century discoveries made invisible phenomena feel newly recordable, especially after X-rays reshaped what “photography” could mean.
3. What can go wrong (and right!) when images look like proof - Why noisy signals, chemical artifacts, and human pattern-finding can produce results that feel conclusive long before they are.
Sources
“Psychicones: Visual Traces of the Soul in Late Nineteenth-Century Fluidic Photography” (Nicolas Pethes, Medical History, 2016)
“Imaging Inscape: The Human Soul (1913)” (The Public Domain Review on Baraduc’s methods and plates)
“Discovery of the X-ray: A New Kind of Invisible Light” (National Museum of Health and Medicine)
🔗 Explore more on our website: mathsciencehistory.com 📚 To buy my book Hypatia: The Sum of Her Life on Amazon, visit https://a.co/d/g3OuP9h
☕ Support the Show: Coffee!! PayPal
Leave a review! It helps more people discover the show! Share this episode with friends & fellow history buffs! Subscribe on your favorite podcast platform
Check out our merch: mathsciencehistory.com/the-store
Music: All music is public domain and has no Copyright and no rights reserved. Selections from The Little Prince by Lloyd Rodgers
🌍 Let’s Connect!Bluesky: https://bsky.app/profile/mathsciencehistory.bsky.social Instagram: instagram.com/math.science.history Facebook: facebook.com/mathsciencehistory LinkedIn: linkedin.com/company/math-science-history Threads: threads.com/@math.science.history Mastodon: https://mathsciencehistory@mathstodon.xyz YouTube: Math! Science! History! - YouTube Pinterest: pinterest.com/mathsciencehistory
Until next time, carpe diem!
A camera was not always needed to “capture” a thought. In the late Victorian era, a few experimenters pressed photographic plates to foreheads and claimed the developed marks were images of the mind.
In this episode of Math! Science! History!, we trace the strange rise of “thought photography,” why it sounded plausible in an age of new invisible forces, and what these experiments reveal about technology, interpretation, and scientific method.
What Develops in the Dark
What you’ll learn in this episode:
1. Who tried to photograph thoughts - How Hippolyte Baraduc and Louis Darget used photographic plates as instruments, then read the resulting traces as evidence of emotion, soul, or mental imagery.
2. Why the idea felt scientific at the time - How late-19th-century discoveries made invisible phenomena feel newly recordable, especially after X-rays reshaped what “photography” could mean.
3. What can go wrong (and right!) when images look like proof - Why noisy signals, chemical artifacts, and human pattern-finding can produce results that feel conclusive long before they are.
Sources
“Psychicones: Visual Traces of the Soul in Late Nineteenth-Century Fluidic Photography” (Nicolas Pethes, Medical History, 2016)
“Imaging Inscape: The Human Soul (1913)” (The Public Domain Review on Baraduc’s methods and plates)
“Discovery of the X-ray: A New Kind of Invisible Light” (National Museum of Health and Medicine)
🔗 Explore more on our website: mathsciencehistory.com 📚 To buy my book Hypatia: The Sum of Her Life on Amazon, visit https://a.co/d/g3OuP9h
☕ Support the Show: Coffee!! PayPal
Leave a review! It helps more people discover the show! Share this episode with friends & fellow history buffs! Subscribe on your favorite podcast platform
Check out our merch: mathsciencehistory.com/the-store
Music: All music is public domain and has no Copyright and no rights reserved. Selections from The Little Prince by Lloyd Rodgers
🌍 Let’s Connect!Bluesky: https://bsky.app/profile/mathsciencehistory.bsky.social Instagram: instagram.com/math.science.history Facebook: facebook.com/mathsciencehistory LinkedIn: linkedin.com/company/math-science-history Threads: threads.com/@math.science.history Mastodon: https://mathsciencehistory@mathstodon.xyz YouTube: Math! Science! History! - YouTube Pinterest: pinterest.com/mathsciencehistory
Until next time, carpe diem!
