The red ochre hand stencil (top centre) was made at least 39,900 years ago in Southern Sulawesi; the animal image was made 4,500 years later | Maxime Aubert
Archaeologists investigating Blombos Cave in South Africa recently announced the discovery of nine faint red lines drawn at least 73,000 years ago on a 4cm long flake of rock. These lines are thought to be the earliest known drawing, probably a fragment of a larger work, since the strokes are cut off at the top and bottom edges of the flake. The pigment is red ochre, a mineral mixture of iron oxides in a clay or chalk matrix.
Ochre colours vary from rich reds to light yellows, depending on the amount of water bound to the iron oxides and particle size. Yellow ochre can be reddened by heating, as it drives off the bound water. Yellow and brown ochre are common constituents of modern paint sets, whether acrylic, oil, watercolour or gouache.
While the drawing is considered remote in terms of time, it is not remote in terms of material or technique. An artist today can walk into any art shop and pick up a pencil of red chalk — powdered iron oxide and chalk pressed into a cylindrical shape. Just as an artist rotates a sheet of paper while making a sketch, attempts to recreate the design revealed that the prehistoric artist rotated the rock.
A drawing is made with dry pigment, while a painting is made with pigment dispersed in a liquid that dries. Paint goes back at least 100,000 years. Two abalone shells uncovered in Blombos Cave in 2011 were found to contain red ochre, charcoal, bone fragments and stone flakes, with telltale signs that the contents had been stirred with a liquid that evaporated long ago, indicating that the shells were mixing bowls for a dark red watercolour. To this day, painters of miniatures favour mussel shells for mixing and holding paint.
Nine faint red lines discovered at Blombos Cave in South Africa are considered a piece of drawing that is at least 73,000 years old
Unlike ochre, charcoal is organic in origin, made from charred wood or other vegetation. The bone fragments in the shells had been burnt before being crushed, perhaps to release the fatty marrow, which would have served to bind the pigments to a surface. Although marrow is not used today, the binders in some artists’ inks are extracted by boiling the skins and bones of fish or rabbits in water. Watercolours and gouache substitute animal-friendly gum arabic, a sticky resin that leaks through the bark of certain acacias.
As for the flakes of stone found in the shells, these originated from the stones used to abrade and crush the ochre, charcoal and bone.