FRIDAY, JULY 10, 2015
BOULDER, CO--If durability is the gold standard of coating performance, here's a paint that passes the test.
An international team of researchers has discovered a milk- and ochre-based paint in southern Africa that dates back 49,000 years.
The paint was likely used for body adornment as well as decoration of stone and wooden slabs, the team theorizes.
This is the first time a paint containing ochre and milk has been found in association with early humans in South Africa, according to Paola Villa, a curator at the University of Colorado Museum of Natural History who is leading the research.
|
|
| University of Colorado Museum of Natural History |
|
The research team discovered the powdered paint mixture residue on the edge of a small stone flake in a layer of Sibudu Cave, a rock shelter in northern KwaZulu-Natal, Africa. |
Ochre is a natural iron-oxide-based pigment that creates a range of colors, from yellow and orange to red and brown. The use of ochre by early humans dates to at least 250,000 years ago in Europe and Africa.
Details of the discovery were recently published online in the journal PLOS One. The excavation was directed by Professor Lyn Wadley of the University of Witwatersrand in Johannesburg.
Milk Mixture
The team discovered the powdered paint mixture residue on the edge of a small stone flake in a layer of Sibudu Cave, a rock shelter in northern KwaZulu-Natal, Africa, the museum explained in a research announcement.
The scientists say the shelter was occupied by humans in the Middle Stone Age from roughly 77,000 years ago to about 38,000 years ago.
The dried paint indicates that the flake may have been used as a mixing tool to combine ochre and milk, or as an applicator, according to Villa.
 |
| ©iStock.com / ajbalmain |
|
The milk used in the paint mixture was likely obtained by killing lactating members of the bovid family such as buffalo, eland (bull pictured), kudu and impala. |
The milk for the paint was likely obtained by killing lactating members of the bovid family such as buffalo, eland, kudu and impala, Villa said.
“Although the use of the paint still remains uncertain, this surprising find establishes the use of milk with ochre well before the introduction of domestic cattle in South Africa,” said Villa.
“Obtaining milk from a lactating wild bovid also suggests that the people may have attributed a special significance and value to that product.”
Cattle were not domesticated in South Africa until 1,000 to 2,000 years ago, she said.
Possible Uses
While ochre powder production and its use are documented in a number of Middle Stone Age South African sites, there has been no evidence of the use of milk as a chemical binding agent until this discovery, according to Villa.
The team used several high-tech chemical and elemental analyses to verify the presence of casein, the major protein of milk, on the stone.
 |
| Yves Picq / CC-BY-SA 3.0 |
|
The modern Himba people in Namibia mix ochre with butter as a coloring agent for skin, hair and leather clothing, according to Villa.   |
Scientists have postulated that ochre was sometimes combined by ancient Africans with resin or plant gum to use as an adhesive for attaching shafts to stone tools or wooden bone handles, Villa said.
Villa said the paint mixture may have been used to preserve animal hides and for body paint.
We just hope that the team finds a pot life to match.
Tagged categories: Coating chemistry; Coating Materials; Formulating; Milk-based paints; Paint application; Research; Stone
