Teacher background information

This elaboration provides students the opportunity to explore the technologies and processes that are involved in the manufacture of pigments and dyes used by Aboriginal and Torres Strait Islander peoples. These technologies and processes require multidisciplinary approaches combining knowledge of geology, biology, chemistry and physics.

First Nations’ Australians have been painting in a variety of forms for at least 28,000 years, making Australia the home of the second oldest evidence of painting found to date.  

Over this incredible period of time, and through their endeavours to construct enduring, bright, crisp and smudge-free pictorial histories, more recently described as art, Aboriginal people accumulated knowledge of paints, pigments and dyes. The raw materials for these are obtained from a variety of mineral, plant and animal sources and their extraction, refinement and production require knowledge from across a range of science disciplines.  

The most commonly used pigments are generally derived from ochre with colours ranging from yellow through brown to red. Ochre is mainly composed of yellowish limonite, itself a mixture of hydrated iron(III) oxide-hydroxides, mixed with clays and sand. Red ochres naturally form in areas with high haematite concentrations. Aboriginal and Torres Strait Islander peoples over thousands of years have developed a comprehensive awareness of the geological distribution of these culturally important mineral resources.  

In regions where red pigment was not readily available from a red ochre source, Aboriginal people traditionally used porphyry (or tuff) to produce iron oxide in a form that could be used as a red pigment. In other areas, yellow ochre from limonite was thermally decomposed and converted into haematite, producing a reddish-brown colour. This process is called calcination, a chemical process involving carefully controlled heat treatment of the mineral source, and is still in use today in the production of commercially available pigments. 

Black pigment may be obtained from charcoal, while white is principally derived from kaolin, although, historically, calcite and huntite were used where they were locally available. Gypsum was also used to produce a fine white pigment using the process of calcination. In this process, calcium sulfate dihydrate (gypsum) is heated until some of the crystalline water is removed, yielding a fine white powder that can then be used as pigment. 

These colouring materials can be applied to surfaces using a variety of techniques. A soft pigment-bearing rock can be used as a drawing implement. Alternatively, the pigment material can be crushed into a fine powder and added to water to form a suspension. Various implements can then be used as brushes to apply the pigment.   

The degree to which pigments adhere to a surface depends on the effectiveness and sophistication of the pigment formulation. The development of a particular pigment formula acknowledges a range of factors including the type and nature of the substrate material, the way that the pigment is applied, and the additives, if any, that have been used as binders and fixers in the pigment mixture. 

Evidence of effective use of iron oxide-based pigments on different substrate materials by First Nations’ Australians may be found across a range of material culture and practices such as shields, boomerangs and bark paintings, and in archaeological remains and rock paintings.  

The chemical knowledge and understanding of the properties of suspensions, binders and fixatives were essential for the development of a water-based suspension that could evenly carry the pigment and enable the controlled application of paint. Similarly, knowledge of the properties of available binding agents such as animal fat, egg yolks and blood was critical to ensuring adhesion of the pigment to the substrate.  

The final essential chemistry knowledge required to paint successfully was an understanding of the role of fixatives, such as orchid sap, that are applied at each layer/stage and on completion. Fixatives are essential for keeping crisp lines and preventing smudging. Fixatives also play an important role in the protection of the paintings and are partly responsible for the incredible durability of Aboriginal pictorial histories. 

Geological knowledge is required in identifying areas and rocks containing the pigment-carrying mineral and knowledge of physics is required to develop quarries and to mine underground. Such activities have been identified as having occurred in many parts of Australia. One mining venture, the Wilgie Mia mine, is believed to be the oldest continuously-mined site in the world. Located east of Geraldton in Western Australia, it was up to 20 metres deep and had a mining face 15 – 30 metres wide. The mining operation at the site included ‘stop and pillar’ techniques to enhance worker safety and the use of pole scaffolding with wooden platforms to allow extraction to occur simultaneously at different heights. The material from the mine was, and still is, highly prized, especially for use as body decoration, and it is estimated that several thousand tonnes of rock have been extracted from this site. In contemporary times, many Aboriginal mines have been exploited for their valuable iron oxides in the commercial use of paints, stains, inks, plastics, pharmaceuticals and cosmetics.  

Biological as well as chemical knowledge are required in dye production for colouring textiles, yarn, baskets, and other materials made from natural fibres. Aboriginal and Torres Strait Islander peoples possess rich botanical knowledge of plants containing coloured substances that can be used to manufacture a variety of colouring agents. Yellow can be obtained from the root of the Pegonolobos reticulatis shrub endemic to the Northern Territory and Queensland; purple from the berries of Haemodorum coccineum, a flowering plant in the same family as kangaroo paw; green from the core of the leaves of the pandanus palm (Pandanus spiralis); black and grey from the leaves of the Quinine tree; and brown from the root of the perennial herb Haemodorum brevicaule. The intensity and shade of the colours vary depending on the soil properties, the part of the plant, and the season of harvesting.  

Chemical knowledge is required in extracting the colouring agents from the plant material and in the understanding of how to fix the dye onto the desired fabrics through the use of mordants. These can be organic substances derived from plant materials, such as tannic acid, or inorganic materials containing polyvalent metal ions, such as aluminium, which are derived from salts and ash. Mordants work by forming an insoluble coordination complex with the dye, which then attaches to the fabric.  

By studying the required multidisciplinary knowledge in producing pigments and dyes used by Aboriginal and Torres Strait Islander peoples, students deepen their understanding of how science knowledge can develop through the confluence of understandings derived from the various disciplines of science. Students will also gain an appreciation of how Aboriginal and Torres Strait Islander peoples’ geological knowledge contributed to the discovery, evaluation and exploitation of commercially important mineral deposits for the production of pigments.