But since the discovery of the Lascaux painted caves in 1940, the work has gone high-tech.
Clottes's team is photographing the paintings and etchings with a regular 35-mm, a digital camera and an infrared camera, which picks up the red-ochre paint better than standard optical devices.
From the Bulletin (Australian weekly magazine) May 25 1999 Insert from Newsweek.
One clue comes from how the images are integrated into the walls.
In the "Goldilocks" chamber, the missing hindquarters of a cave bear drawn in red ochre seem to lie within rather than on the rock.
The presence of 55 ancient bear skulls, including one carefully placed on a fallen rock as if on an altar, suggests a cult of the cave bear.
And that may explain why the cave artists chose Chauvet: dozens of hollows in the floor indicate that the enormous bears hibernated there. On the 30-foot-long "panel of the horses," the charcoal marks of torches being knocked against the wall were made after the paintings, says Conkey: the marks are superimposed on the mineral sheen that covers the figures.
"The bear seems to come out of the wall," says Clottes.