Hundreds, thousands of years exposed to the elements often leave ancient art hard to see. Famous sites like Chauvet, Altamira and the Great Gallery are well preserved but some important rock and cave art sites are weathered almost beyond recognition. How do we see rock art that is mostly weathered away? Mathematics, NASA and rock art enthusiast Jon Harman have a solution. It is an image analytic program Harman developed called DStretch.
Barrier Canyon Style Petroglyphs in a side canyon of Ferron Creek. Emery County, Utah. See what it looks like after DStretch on the next page.
The program uses a method called decorrelation stretch, which was originally used by NASA to improve remote sensing images of Mars. DStretch takes the NASA algorithm but optimizes it for rock art. The program analyzes photographs of rock art sites, and then shifts the images’ color to highlight designs and patterns that have faded away or otherwise become invisible to the naked eye by providing more contrast within the image. The program is especially useful when it comes to faded colors, particularly reds, yellows, blacks, and whites, but it is also works on etchings and other rock art forms. The results are a false color image that is often much more detailed than the original.
Esplanade Style Polychrome Panel, Mojave County, Arizona
This is the type site for Esplanade style polychrome rock art. Known from only 25 sites it is some of the most enigmatic and beautiful prehistoric art in North America. There are fewer than 25 examples of Esplanade style rock art all are located in Mojave County Arizona. As such it is one of the least studied types of North American rock art. Age estimates range from archaic southwest (8,000 BCE) to pre-Fremont (500 BCE).
The style stands out for its tremendous detail. See the close-up image of part of the panel below. Some of the anthropomorphic figures are presented in "x-ray" style. Eyes often have lashes. The images are finely rendered.
Artists who created the ancient masterpieces that we appreciate today—cave paintings, murals on cliff walls, countless carvings, and other artifacts—left no written records about the worlds in which they lived. This often makes it difficult to know when they lived. Fortunately, modern technology has helped scientists develop several dating methods to accurately date ancient art sites.
Scientists used carbon 14 dating to determine that the charcoal used at Chauvet was over 30,000 years old
Ten negative handprints in Fish Canyon, Bears Ears National Monument, Utah
If there is a single symbol that could stand for all of humanity it is the negative handprint. I've seen the negative handprint reproduced on 6 continents and across all ages of human creativity. From the Paleolithic to modern times the images persists in our visual vocabulary. They may well be the very first artistic expression. To me, they are the original 'selfie' the very first way that people recorded their passage. That urge to leave a visual mark that says "I was here" is uniquely human.