How well a painted image will last on a cliff or boulder depends upon a number of factors. One factor, of course, is the kind of rock it is painted on, how hard or how soft? Another factor is the weather itself and the sites exposure to it. Is it directly in the Sun’s fading rays, is it in a location that is hit by rain, etc.? Another, and perhaps most important, factor is the composition of the paint itself. Is the pigment durable or fugitive? How thoroughly does the binder in the paint harden and hold on to the rock surface?
The images painted in one section of China have long mystified scientists with their clarity and appartent durability. “The Zuojiang Huashan Rock Art Cultural Landscape was created over the course of nearly 700 years, between the fifth century BCE and the second century CE, by the Luoyue people – a matriarchal, hunter-fisher-gatherer society that lived in southern China. The images are found across 80 sites along a 260-kilometer stretch of river cliffs. Given that the area is battered by regular monsoons, the art is remarkably intact, especially compared with murals made hundreds of years later in other parts of the country.” (Sagar 2026) Normally, frequent monsoon rains would be thought to doom painted images to quick destruction.
These painted images, however, act very different – they are exceedingly durable. “The pigments are so firmly bonded to the bedrock that when peeling occurs, it is the limestone layer itself that detaches along with the pigments,” says Meng Wu, a chemist at Shandong University. “The material stability of this art has long been an unsolved mystery.” (Sagar 2026)
“These paintings are bound to the rock so well that scientists had to use electric drills to scrape off samples for testing, which revealed that the paint contained lime, red clay, and blood from women who’d just given birth.” (Spitz 2026) The most surprising component of the paint used was blood, which came from both humans and animals. “The human portion contained two proteins that were linked to pregnancy, breastfeeding, and female reproductive biology. Therefore the team concluded that these proteins likely came from women who had very recently given birth, and that the blood came from routine postpartum bleeding.” (Spitz 2026) This is a likelihood, not a certainty, as the proteins in question are not totally unique to women and childbirth. Much of the durability of the red paint is due to the lime and red clay ingredients setting up in a reaction much like cement. Then, adding the proteins from blood, we can expect this to only enhance the durability of the paint.
As the Luoyue creators of this rock art are believed by historians to have been a matriarchal society, the use of postpartum blood in the paint may have had a deeply spiritual significance to the people. Therefore the act of creating the rock art may have also involved significant ritual contexts. At least that makes a great deal of sense.
NOTE: One image in this column was retrieved from the internet with a search for public domain photographs. If any of these images are not intended to be public domain, I apologize, and will happily provide the picture credits if the owner will contact me with them. For further information on these reports you should read the original reports at the sites listed below.
REFERENCES:
Sagar, Soumya, 2026, Were these ancient rock images painted with human blood?, 12 August 2026, https://www.science.org online. Accessed online 13 August 2026.
Spitz, Ella, 2026, Scientists Just Uncovered The Secret Behind The Durability Of China’s
Ancient Huashan Rock Art: Human Blood, AllThatsInteresting.com, 29 July
2026, https://allthatsinteresting.com/china-huashan-rock-art-blood.
Accessed 13 August 2026.
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