Because Niépce's exposure of Le Gras took about eight hours, the sun moved from east to west during the process, causing the finished image to appear illuminated on both sides of the building.
Notes on verification
Widely repeated traditional account corroborated by Wikipedia, PetaPixel, and other photography history sources, but modern recreations of Niépce's process suggest the actual exposure may have lasted days rather than eight hours, so the specific duration is debated even though the sun-movement/dual-illumination effect is well documented. [cascade flags: wikipedia_dropped_other_sources_exist | tier=unverified indep_score=0.3 clusters=2 claim_tier=notable] [rescored 2026-09-15: curated origin-host map (PR #65); unclassified hosts no longer scored as aggregators]
Sources
- History of photography | History, Inventions, Artists, & Facts - Britannica (seed:geography_and_travel)
- https://petapixel.com/the-first-photo/ (corroboration)
- https://aestheticsofphotography.com/view-from-the-window-at-le-gras-nicephore-niepces-first-photograph/ (corroboration)