The display of more than 100 works by Aboriginal painters has presented challenges to the conservators aiming to extend the lifespan of the artworks. Those looking after the show, called Old Masters: Australia's Great Bark Artists, are a team with diverse skills.

Team head Nicki Smith, who has experience with bark paintings, said one of the biggest jobs involved bandaging the backs of the works so they did not break apart.

Two-thirds of the paintings needed intervention, because some works in the show - including those by artists Yirawala and Narritjin Maymuru of western and eastern Arnhem Land - were produced up to 50 years ago.

Conservators spent more than a week working on one painting.

''Think of what happens when bark falls from a tree and after a while it begins to split,'' Ms Smith said.

''That's what happens to the paintings.''

Despite this, she said the paintings would survive hundreds of years if cared for properly.

Another challenge was that the paint - a mixture of ochre clay and charcoal - flakes off over time because it is so dry.

This is where the conservators used the fish protein called isinglass, as well as Japanese red seaweed extract, bought from Germany at a cost of $115 a gram, to keep the paint in place.