You could use this type of mixture to prepare animal skins, to put on as body paint, or to paint on the walls of the cave, but it is difficult to be sure how it was used," said Francesco d'Errico, a study co-author at the University of Bordeaux. "The discovery is a paradox because we now know much better how the pigment was made than what it is used for." The team has unearthed other artefacts from early humans at the cave. In 2004, it uncovered a collection of 75,000-year-old decorative shell beads at Blombos cave, some of which had been painted with ochre. Piecing together the process from the instruments they found, Henshilwood said the artists used small quartzite cobbles to hammer and grind the ochres into a powder, which was then poured into the shell and mixed with charcoal, burnt and broken bone, and the unidentified liquid. This is the first known instance for deliberate planning, production and curation of a compound," Christopher Henshilwood at the University of Bergen told Science, adding that the finding also marked the first known use of containers. "It's early chemistry. It casts a whole new light on early Homo sapiens and tells us they were probably a lot more intelligent than we think, and capable of carrying out quite sophisticated acts at least 40,000 to 50,000 years before any other known example of this kind of basic chemistry," he added.

Tiny grooves at the bottom of the shells may be scratch marks caused by sand grains when the artist mixed the paint with a finger. "From time to time they were scratching the bottom when their finger was moving some of these little grains," said d'Errico.One of the artists' kits came with a slender bone from the front leg of a dog or wolf. One end of the bone had been dipped in ochre, leading the scientists to conclude it was used as a primitive paintbrush. Along with ancient flakes of charcoal, researchers found a "high water mark" on the shells' inner wall, evidence that an unknown liquid, probably urine or water, was added to make the paint more fluid. Other bones, including the shoulder blade of a seal, were among the ingredients for making the pigments. The bones were probably heated in a fire and the marrow fat used as a binder for the paint. One of the toolkits, which was found next to a pile of different instruments, was more complex and particularly well preserved, with its intact shell coated with red pigment. A second shell, found close by, was broken, but its grinding stone was coated with red and yellow pigments, suggesting it had been used more than once.