Nicéphore Niépce's heliography process used bitumen of Judea mixed with lavender oil, in which sunlight hardened the solution in exposed areas while unexposed portions remained soft and could be washed away.
Notes on verification
Confirmed by multiple independent, credible sources including museum institutions and historical references, consistent in describing the bitumen hardening/washing mechanism. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.833 clusters=3 claim_tier=notable]
Sources
- History of photography | History, Inventions, Artists, & Facts - Britannica (seed:geography_and_travel)
- https://www.hrc.utexas.edu/niepce-heliograph/ (corroboration)
- https://blog.scienceandmediamuseum.org.uk/a-z-of-photography-joseph-nicephore-niepce-first-photograph/ (corroboration)
- https://www.amusingplanet.com/2021/10/the-first-photograph-in-history.html (corroboration)