Thursday, December 12, 2019

Juxtaposition and Superimposition Show What Became of the Original Americans...,

Not a repeat - it starts at a specific part of the video - so just click it. |  What’s more, a flickering flame in the cave may have conjured impressions of motion like a strobe light in a dark club. In low light, human vision degrades, and that can lead to the perception of movement even when all is still, says Susana Martinez-Conde, the director of the Laboratory of Visual Neuroscience at the Barrow Neurological Institute in Phoenix, Ariz. The trick may occur at two levels; one when the eye processes a dimly lit scene, and the second when the brain makes sense of that limited, flickering information. 

Physiologically, our eyes undergo a switch when we slip into darkness. In bright light, eyes primarily rely on the color-sensitive cells in our retinas called cones, but in low light the cones don’t have enough photons to work with and cells that sense black and white gradients, called rods, take over. That’s why in low light, colors fade, shadows become harder to distinguish from actual objects, and the soft boundaries between things disappear. Images straight ahead of us look out of focus, as if they were seen in our peripheral vision. The end result for early humans who viewed cave paintings by firelight might have been that a deer with multiple heads, for example, resembled a single, animated beast. A few rather sophisticated artistic techniques enhance that impression. One is found beyond the Hall of Bulls, where the cave narrows into a long passage called the Nave.

High on the Nave’s right wall, an early artist had used charcoal to draw a row of five deer heads. The images are almost identical, but each is positioned at a slightly different angle. Viewed one at a time with a small circle of light moving right to left, the images seem to illustrate a single deer raising and lowering its head as in a short flipbook animation. 

Marc Azéma, a Paleolithic researcher and filmmaker at the University of Toulouse in France, has studied dozens of examples of ancient images that were meant to imply motion and has found two primary techniques that Paleolithic artists used to do this. The first is juxtaposition of successive images—the technique used for the deer head—and the second is called superimposition. Rather than appearing in sequence, variations of an image pile on top of one another in superimposition to lend a sense of motion. Superimposition can be seen in caves across France and Spain, but some of the oldest examples come from Chauvet cave in France’s Ardèche region. Burned wood and charcoal streaks along Chauvet’s walls indicate that campfires and pine torches lit the cave.