Paint pigments used in caves
Ochre, manganese, kaolin, charcoal
Colour pigments were not just used for painting caves. Human species like Homo heidelbergensis, as well as Neanderthals, were mixing and employing colour pigments thousands of years before the advent of cave painting. For more see: Cave Painting: History, Themes, Techniques.
In fact, the use of artificial colours by hominins - in the form of red ochre - can be traced back at least half a million years.
In Africa, for instance, there is reliable evidence of ochre use from about 500,000 BC onwards.
This is clear from evidence discovered at several South African sites of the Late Acheulean and Fauresmith industries.
Sites yielding traces of pigment include: Kathu Pan 1, Canteen Kopje and Wonderwerk Cave.
Other traces of early ochre use have been found in Kenya, Zambia and Ethiopia.
As there seems to be no apparent centre of innovation, it appears that pigment-use was a feature of Stone Age culture as far back as the Lower Paleolithic.
Since 300,000 BC, ochre 'tool-kits' have been recovered from more archaeological sites in Africa, Europe and Australia.
At Blombos Cave, for instance, researchers unearthed a 'paint workshop' with a wide range of paraphernalia such as bones, charcoal, grinding-stones and hammer-stones, as well as abalone shell containers and other mixing vessels. It included more than 8,000 pieces of ochre, dating to between 75,000-100,000 BC, including many which had been formed into 'crayons'.
The paint workshop at Blombos contained a wide range of paraphernalia for processing, mixing and applying red ochre, but no evidence of contemporaneous cave art was found. Clearly the pigments were being used for other purposes, such as body painting, face painting, or protection from the sun - rather than cave art.
Similar finds were made at sites in Australia, such as the Arnhem Land rock shelters Nauwalabila 1 (53,000 BC) and Malakunanja II (53,000 BC), where used lumps of red ochre were discovered, but there was no sign of any Aboriginal painting.
In his book The Art of Prehistoric Man in Western Europe, the French prehistorian Andre Leroi-Gourhan (1911-86) describes how the floor deposits in many paleolithic caves and rock shelters in Europe, often contained a layer of reddish ochre, up to 20 cm (8 inches) deep.
This shows that pigments were widely used by Stone Age people to colour their bodies, their animal skins and even their weapons, as well as their cave drawings. In short, pigments were a regular feature of Stone Age life.
Stone Age paint contained three main ingredients: pigments, binders, and extenders.
Stone Age pigments were first obtained from organic animal and plant material. But by the mid-Gravettian (about 26,000 BC), prehistoric artists had discovered that inorganic mineral pigments retained their colour for much longer.
It's possible they saw that colours in iron-rich deposits in the earth did not fade with the changing environment.
Thereafter, dyes derived from animal and vegetable sources were limited to colouring hides, clothing, artifacts, hair and the human body.
The two main pigments used in prehistoric art were red and black.
A binder is an adhesive substance that holds the texture of the paint together and helps the pigment to stick to a surface. Common prehistoric binders included cave water, saliva, animal fats, vegetable juices, plant sap, urine, bone marrow, blood, and albumen.
An extender is a substance which was added to the paint to increase its volume or bulk (thus saving on the pigment), and to prevent the paint from cracking as it dried. Typical prehistoric extenders included feldspar, biotite, ground quartz, and calcium phosphate (from crushed animal bone).
The pigments were first made into a powder by grinding them in mortars created from animal shoulder bones, or abalone shells, or natural stone hollows in caves. Sometimes, the pigment was heated before being ground up. Then the powder would be combined with one or more binders and extenders, and made into a paste.
The Stone Age colour palette was based on three basic colours: red, black and yellow. To obtain these colours, and other secondary hues, cave painters relied on five important mineral-based paint pigments.
Also known as hematite, limonite, ferrous oxide, goethite and specularite, ochre consists of fine clay and iron oxide, and comes in a variety of colours. These include red, orange, yellow, purple, and brown.
Limonite, containing iron hydroxide, is the main ingredient of all the ochre pigments.
Ochre is found all over the world, and was used from the Middle Paleolithic onwards, and later by every Mesolithic and Neolithic culture, as a decorative material for the human body and hair, as well as cave paintings, ancient pottery, and numerous artifacts.
Red ochre pigment, for instance, has been found in almost all decorated paleolithic caves throughout prehistory.
Sienna is another earth pigment that with both iron oxide and manganese oxide. Raw sienna is yellowy-brown, but when heated, some of it turns into hematite and takes on a reddish brown hue, known as burnt sienna.
Another earthy pigment, typically brown or reddish-brown, umber contains oxides of both iron and manganese. It is darker than the other earth pigments, like ochre and sienna, although its hue varies according to its manganese content. The more is has, the darker it is. Also, umber turns a darker brown colour, known as burnt umber, when heated. Although Umbria in Italy was the first region where Raw Umber was extracted commercially, this type of iron oxide is found in many other parts of the world, and the finest grades are attributed to Cyprus.
Different manganese oxides provided Stone Age painters with different black hues. These included: the dark steel-grey to black manganite, the brownish-black hausmannite, the jet-black groutite, and the rarer dark brown or brownish black todorokite and birnessite.
Kaolin (china clay or kaolinite) is one of the world's most common minerals. Soft and white, kaolin was used as a white colour pigment. Its whiteness and hardness were increased by heating.
The typical Stone Age palette included a mixture of primary, secondary, tertiary, and composite colours.
Painters developed two out of three primary colours (red and yellow), two secondary colours (orange and violet), and at least three tertiary colours - Red-Orange, Yellow-Orange, Red-Violet - which are created by mixing a primary with a secondary.
In addition, they produced other colours, like brown, directly from brown-coloured minerals.
Paint was applied to the cave walls using a variety of smearing, dabbing, brushing and spraying techniques.
Cave painting wasn't simply a matter of gathering enough paint and paint brushes to create pictures on cave walls. Archaeologists believe that artists went to great effort to find suitable locations for particular rock paintings. Importance was given to the visibility and archaeoacoustics of the location, as well as how well the planned picture fitted with the contours of the surface.
At Niaux Cave, for instance, there is one last black painting, which is almost hidden from view. It is located at the extreme end of the Salon Noir, in a deep recess known as the Cul-de-Four. This unidentified image - either of a human figure, or part of an animal - seems to disappear into the very cave wall itself.
Once a location had been selected for a painting, the artist prepped the area by smoothing the stone surface, or removing loose material. Only then would drawing or painting commence.
Elevated locations required scaffolding. Holes found drilled in the walls of caves most likely were created to support wooden beams and ladders. Lack of light was another issue in many caves.
At Lascaux cave, for instance, archaeologists recovered more than 100 oil lamps from the cave floor. Most were made out of limestone plates with a central depression for animal fat.
Once the preparation was finished, the painter could begin. Not surprisingly, painting habits varied from artist to artist. Some painters made preparatory sketches, or rock engravings, before using any paint, while others started painting immediately.
Given the difficulties they faced, painters developed a reasonably wide Stone Age colour palette, but some colours are missing. For instance, blue (an important primary colour) is missing, as is green (a secondary colour).
The absence of blue is easier to understand, due to the scarcity of blue minerals. Only later was it obtained from powdered azurite (copper carbonate) or the mineral lazurite.
But green minerals, like malachite and green earth (terre verte), are relatively abundant and are perfectly stable. Did the dim light in caves affect the colour's brightness or luminosity? Was it too dark to be properly seen? It seems unlikely. After all, browns and purples have a similar level of luminosity.
Most paint pigments used in caves were procured locally. In the Dordogne, and other areas where clusters of deep caves existed, ochre mines would be shared between the respective sites.
Generally speaking, it seems cave artists went to great effort to source their pigments and dyes, travelling 40 kilometres or more to obtain supplies. They also relied upon a regular supply of animal bones for black pigments, binders and extenders, as well as a regular quantity of charcoal wood for drawing.
The earliest known figurative painting emerged in SE Asia: see the red/purple warty pigs in the Sulawesi cave paintings (43,500 BC), and the reddish-orange images of wild cows in the East Kalimantan caves (38,000 BC).
Rock paintings found in Australia might be older still, but securing firm dates has proved impossible with present dating technologies.
In Europe, the use of paint pigments by prehistoric artists is well documented, during the Upper Paleolithic. Here's a brief outline.
There were only four colours in the Aboriginal Stone Age palette: red, yellow, white, and black. This palette was quite typical in northern areas, less so in the south, being unknown in the southwest. It is not known if this difference was due to lack of red and yellow ochre.
Pigments employed in aboriginal rock art were first watered down. Then, using his finger or a piece of frayed wood used as a brush, the artist would apply a background tint of (usually) yellow ochre. Once it dried, he would draw a broad red line, or some other motif, like a snake or crocodile.
In this way Australian painters decorated rock shelters, as well as domestic items like the handle of a tool, a wooden basin, or a canoe. These artistic markings composed of red, black or white lines on a yellow background became a form of language.
The palette of colours used by Stone Age cave painters in Africa, consisted largely of earth pigments. Reds and browns from hematite or or other clays; yellows, orange and reds from ochre; whites from zinc oxide; blues from iron and silicic acid; blacks from charcoal or burnt bone. The blue pigment produced in Africa is unique and does not appear in the cave art of Europe.
(1) "The Use of Ochre and Painting During the Upper Paleolithic of the Swabian Jura in the Context of the Development of Ochre Use in Africa and Europe." Sibylle Wolf, Rimtautas Dapschauskas, Elizabeth Velliky, Harald Floss, Andrew W. Kandel, Nicholas J. Conard. Open Archaeology 2018; 4: 185–205.
(2) "Engraved ochres from the Middle Stone Age levels at Blombos Cave, South Africa." Henshilwood, C. S., d’Errico, F. & Watts, I. (2009). Journal of Human Evolution, 57, 27-47.
(3) "Ochre Use in the Middle Stone Age at Sibudu, South Africa: Grinding, Rubbing, Scoring and Engraving." Hodgskiss, T. P. (2013b). Journal of African Archaeology, 11(1), 75-95.
(4) "Color: A Natural History of the Palette." Finlay, Victoria (2003). Random House. ISBN 0-8129-7142-6.