Earth Pigments: Did Aboriginal people use Blue Ochre?
Ochre is the name given to a family of natural earth pigments containing iron oxide. The name is also loosely associated with any pigment that may be derived from basic processing by the crushing or grinding of minerals or mineral aggregate (rock and clay).
Natural earth pigments have formed an important part of the varied cultures of Australia’s First Peoples for as long as humans have walked the continent. The earliest confirmed example of ochre usage in Australia as both a form of ceremony and artistic expression is the ritual burial of a Koori warrior known as ‘Mungo man‘, at Lake Mungo in Mutti Mutti, Barkindji, and Ngiyampa country in south western New South Wales. Buried carefully in a sand dune between 40,000 and 42,000 years ago, Mungo man was laid to rest on his back, with his hands crossed in his lap and his body sprinkled with red ochre. The ochre had been obtained from a deposit in another locality, as it is not naturally found at Lake Mungo.
Earth pigments are found in varying forms in all regions of Australia. However, there are a number of celebrated cultural sites found in different parts of the continent where ochre was traditionally mined, both as a local resource and as a commodity for trade with neighbouring Clans and Nations. These sites were important due to the high quality and range of the materials extracted from them. Such sites include the Ochre cliffs in Yantruwanta country, South Australia, and Wilgie Mia in Wajarri Yamatji country, Western Australia.
A wide range of earth colours are found in Australia, from the commonly recognised palette of red, orange, black, white, yellow and brown, through to purple, pink, green, and turquoise. Blue pigment is a notable exception. There are no known local sources of the mineral Lapis Lazuli, and Vivianite which is also known as ‘Blue Ochre’ is not known to have been utilised by Koori people in the areas in which it occurs. However, Koori people began using imported blue pigment soon after their initial encounters with Europeans. Particularly, certain blue laundry dyes were utilised in decorating shields, boomerangs and other weapons where such dyes were readily available.
Colour may often be associated with a particular usage and meaning. In many cultures across the continent white is a colour used to represent mourning and loss. Yellow in many situations is associated with women’s ceremonies. Whereas red may in some cultures represents an association with war, whilst it may also be seen as the colour of celebration or ceremony.
- Red ochre is hematite (anhydrated oxide), and is the most common form of earth pigment, other than a basic brown ochre.
- Purple ochre is identical to red ochre in composition, but refracts light differently due to a larger average particle size.
- Yellow ochre is limonite (hydrated iron oxide). With heat treatment the composition of yellow ochre may be altered, resulting in the production of orange, red, and umber ochres.
- Coal and charcoal are used in the production of black pigment. Charcoal however requires a binder to be utilised in order to counter the material’s water repellent properties.
- Pink and orange ochres are common. However, they may also be produced via basic colour mixing.
- Green and turquoise ochres or clays are rare, thus they carry a particular importance in ceremony and art in the regions of Australia where they are known. Such ochres tend to occur in small deposits, often in the presence of a larger deposit of the more common ochre colours.
- White pigment is obtained from a range of minerals found as clay, and these are generically known as ‘pipe clay‘.
Fixatives are often employed in the production of ochre based paints. These enable a pigment to adhere to a surface, and also act to further the longevity of the final artwork. Fixatives and binders have historically included plant resins and gums, orchid sap, honey, egg, blood, saliva, and animal fat. Contemporary binders include refined ‘Gum Arabic’, and P.V.A glue.