(CNN) -- It's one of the oldest forms of human creativity on the planet, dating back thousands of years -- yet it's only in the last few decades that the art world has really caught on to Aboriginal painting.
For generations, Aboriginal elders passed on traditional Dreamtime stories and tribal knowledge through the use of bark, rock and body art, using natural pigments applied in dots and lines with fingers and twigs.
It took a humble school teacher in 1970s Papunya, a small settlement in Australia's Western Desert, to become the first white man to recognize this rich cultural heritage. After giving art classes to his young Aboriginal pupils, he encouraged their elders to get involved.
"Geoffrey Bardon began encouraging the senior men in the community to paint on whatever they could find -- tiles, bits of board -- so they could record their stories in a more permanent way," said Francesca Cavazzini, an expert at Bonhams Sydney, which is holding an Aboriginal art auction on June 28.
"The men embraced it very enthusiastically, and some of those first paintings are still around today and are very collectible," she added.
Among them is a work by Johnny Warangkula Tjupurrula, featuring desert iconography in enamel paint on chipboard, which will be on sale at the auction.
In those early days, many artists simply transferred their traditional paintings and symbolism from bodies and bark onto board. But as government-funded art centers sprang up, giving access to modern materials, the work moved away from dot painting and became more experimental -- incorporating brighter colors and a more painterly form.
"A whole new world opened up with the introduction of acrylics and canvas -- the changing of materials let their creativity just really open up," said Adrian Mibus, director of Whitford Fine Art gallery in London, which is currently holding a selling exhibition of Aboriginal art.
"In the 1980s, people like Emily Kame Kngwarreye started doing paintings which at the time were a totally new experience -- large finger paintings with swirls of color. She was deemed to be a master."
"It's very interesting to see the development when they move to bigger canvases and pare the iconography right down," added Cavazzini. "Often the style is very abstract now, but you'll often see elements of the landscape like sand dunes, done in a beautifully minimalist way."
The latter applies to Lily Kelly Napangardi, an artist included in the Whitford exhibition, who paints from the bird's-eye view perspective typical of Aboriginal landscape art.
However, senior lawmen in some Aboriginal tribes have been strict about what can and cannot be painted. "I have to stay within the law when I paint. I can't paint someone else's country or steal their identity," explained the Yolngu Aboriginal artist Gunybi Ganambarr.
"I make art which shows the law I have learnt from my elders, but I make it a new way that comes from inside. I use things that Yolngu artists haven't used before, like wire and steel and plastic, as well as bark and ochres. These are all things that I find on my land so I can use (them) to paint my land," he added.
It wasn't until the 1990s that a secondary market for Aboriginal art developed, but it quickly began to make serious money. "Aboriginal art had never appeared at auction before, and it was incredible to see the reaction to it," said Cavazzini. "Collectors were fighting over it."
By the turn of the century it had become a major business, and in some cases art centers were making enough money to become self-sufficient.
According to Bonhams, Emily Kame Kngwarreye has achieved AUS$1 million at auction and the market peaked in 2007, before the global financial crisis, with the AUS$2.4 million sale of a work by Clifford Possum Tjapaltjarri.
More recently, prices have been dropping -- with a Deutscher and Hackett auction in Melbourne this month grossing just AUS$1.25 million from estimates of double or triple that.
Yet for many Aboriginal artists, the motivation is not financial. "The current correction in the speculative end of the market is not only of no concern to the artists, they are generally unaware of it," said Will Stubbs, coordinator of the Buku-Larrnggay Mulka art center in North East Arnhem Land. "Their concern is with the ceremonial and spiritual health of their land."
"For the artists, their motivation to paint is still the same," agreed Sally Clifford, director of Warlayirti Artists Aboriginal Corporation in Balgo. "Despite the economic climate, they are still wanting to share their Tjukurrpa (dreaming story) to people all over the world."
CNN's Greg Hughes contributed to this article.
