The Three Gums 1913-20, by Sir Hans Heysen, and Motherhood, 1941, by Nora Heysen, have been loaned to the National Gallery of Victoria for their exhibition Hans and Nora Heysen: Two Generations of Australian Art, which opened last week.

The NGV had planned to buy The Three Gums in 1921 but reneged on the deal because of anti-German prejudice at the time, so the Ballarat Gallery made the purchase and the large painting has been on display almost continuously ever since.

And Nora Heysen's Motherhood came in to the AGB collection after it came second in the gallery's George Crouch Prize - at the time the second-richest art award in the country. Although it did not win, the gallery director decided to buy it from the artist.

While Hans was known for his landscapes, Nora built her reputation on portraits and still-life painting. She became the first woman to win the Archibald Prize, and the first woman to become an official Australian War Artist, serving during World War II.

Art Gallery of Ballarat curator Julie McLaren said it was a big logistical exercise lending artworks to other galleries.

"We have to factor taking it off display and replacing it with another work, and The Three Gums is a very large work," she said.

"It's one of Hans Heysen's most epic paintings and definitely a star in our collection. It's been hanging pretty much continuously from when it was acquired in 1921."

A mechanical lifter was required to take it off the wall and a crate had to be built for its safe travel.

Art Gallery staff prepared condition reports on the paintings, going over them with a magnifying glass to record any damage or potential areas where paint may be lifting or become unstable. Staff then accompanied the works to Melbourne to supervise their unpacking and installation in the exhibition.

Ms McLaren said the inclusion of the works in the Hans and Nora Heysen: Two Generations of Australian Art exhibition was a vote of confidence in the Ballarat collection.

"We loan out a number of works each year to exhibitions all over Australia. It shows that previous directors or management boards of the gallery, from its inception 130 years ago, had really great foresight to be able to select works for our collection that were representative of Australian art of a particular period.

"It shows we have always had really great people involved in the gallery who have a really keen eye in terms of recognising wonderful works for our collection."

Hans' grandson and Nora's nephew Chris Heysen, who attended the exhibition opening along with other family members, said it was wonderful to see all the paintings in the one place.

He fondly remembers his grandfather and aunt and as a child was often out in the paddocks with his grandfather when he was sketching around his property The Cedars in the Adelaide Hills, which is now open to the public.

"Many of the works in the exhibition are from my family home, my parents'' family home because they were from my grandfather. One of the lovely things for me is to see some of the pictures that were there when he was still alive, but were dispersed after he died," he said.

He vividly remembers sitting for a portrait for his aunt when he was about five or six, and earning a stern rebuke for fidgeting while she painted.

Hans and Nora Heysen: Two Generations of Australian Art is at the NGV Australia in Federation Square until July 28.

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