In fact, all of them had sold. It was the moment that he was forced to accept that perhaps his recent decision to quit his day job and focus full-time on his art - a dicey move even for artists today - had been the right one.

By that time, he had been painting landscapes since he was a teenager in the 1890s, even while working punishing hours as a draper's assistant to support his family, and his work, from the outset, had been well received and admired.

He also had fans - Norman Lindsay, of all people, would one day describe him as "the greatest painter of pure light the world has ever seen" (JMW Turner, eat your heart out). And his landscapes certainly stood out then, as they do today, for their thoughtful composition and masterly brush-strokes. He won the Wynne Prize seven times, from 1916 onwards, and his work is found in all the major art galleries in Australia, as well as several private collections. One of his most famous paintings, Spring Frost, is one of the Art Gallery of NSW's most popular works, although most people know it as "the one with the cows" and would be hard-pressed to name its creator.

Why, then, is his name still so relatively unfamiliar in Australia?

It's a question that Deborah Clark, curator at Canberra Museum and Gallery, is still trying to nut out, but she hopes that a major new exhibition at the gallery will help change the public's perception of an important Australian artist who, it turns out, had a lasting connection to the early landscape of Canberra.

Elioth Gruner: The Texture of Light has been several years in the making, and will be the first survey of Gruner's work since a show at the Art Gallery of NSW in 1983.

"I think, and I'm not alone in this, that he was one of the most important landscape painters we've ever had in Australia," Clark says, during a behind-scenes look at some of the 70 works that will hang in the show.

Even propped up in trolleys or laid out on worktables, Gruner's works glow with what Clark describes as "searching, quiet, painterly and sometimes enigmatic interpretations of the Australian landscape".

And it's the ones of the landscape around Canberra - a stand of poplars, say, or a panoramic mountain view that still exists, unchanged, on the drive to Cooma - that can cause your breath to catch in your throat.

Born in New Zealand in 1882, Gruner was the younger son of a Norwegian father and Irish mother. The family moved to Australia when he was just a baby, and, from an early age, his mother encouraged him to paint. He started art classes at the age of 12 with art teacher Julian Ashton, but when he was 14 he was forced by the family's straitened circumstances to work full time, although he still went to art classes in his hours off.

"That was before there were really good labour laws, so he worked hideously long hours - all day Saturday and one Sunday off a month. [It was] absolutely Dickensian," Clark says. "It was said that when he went to night classes at Ashton's, he would arrive sometimes and his feet were bleeding, so it was a pretty hard life."

He worked full-time as a draper's assistant until he was 30, in 1912, and would continue to support his mother until her death in 1922. But as far back as 1896, Gruner began submitting work to the Society of Artists, and a still-life called Violets was hung in its spring exhibition of 1901. He exhibited with the society regularly for the rest of his life, but from the start his work was noticed.

"We've got half a dozen of these exquisite little beach paintings which are quite Condor-esque, quite impressionistic, and then beautiful paintings of Sydney Harbour too, so that was his place, that's where he worked, and they were well received and he was much admired," Clark says.

"He had a very assured painting style and that only got better. He was a master of the brush, and had terrific compositions. Light became his thing, and his composition was fantastic. Many artists who achieve good composition actually don't paint all that well - someone like Drysdale for example, did fabulous paintings but very clunky in the application. But Gruner really worked at that, very hard."

It was around the outbreak of World War I that Gruner, along with fellow artist Gordan Esling, discovered Emu Plains, a stretch of farmland west of Sydney, in the shadow of the Blue Mountains.

"It was all just grassland and farmland, and that's where he painted his extraordinary paintings of the farm and cows, in the early morning particularly," says Clark.

"He really did become a master of light, and that's where it kind of starts really. They're astonishing paintings."

It was also the beginning of Gruner's travelling lifestyle, and established him as one of the great plein air artists.

"He hadn't exactly exhausted the Sydney Harbour subjects, and he continued over the years to return to some of those, such as Mosman and Cremorne Bay, but really, further afield became the thing," Clark says.

"Paintings without houses, without settlements, just the raw landscape. He first went up northern NSW, round the northern rivers and further west a bit, beautiful coastal scenes up there as well, and he enjoyed the landscape and the light."

He also, in 1923, after his mother died, took the opportunity to travel overseas. He was nominated to manage a major exhibition of Australian art at the Royal Academy in London, and remained in Europe for two years, living from sales and commissions. He travelled through France and Italy and, like many artists before him, the experience - especially seeing the works of Paul Gauguin and Paul Cezanne up close - changed him and his work, at least temporarily.

But both before and after that trip, he travelled the region of northern NSW, visiting pastoralists and asking to stay on their properties so that he could paint the area, often returning the favour with the gift of a small painting. And, some time in the early 1920s, he discovered the Canberra region.

"That's the great thing for us, because he painted extensively the Cooma-Monaro, the Southern Highlands, the Murrumbidgee River corridor, as early as the early 1920s. We have him first in 1921, though he might have come earlier," says Clark.

Gruner was friends with the artist George Lambert, whose famous painting The Squatter's Daughter is set at the Ryrie family's Micalago property in 1923 or 1924.

"Lambert was a big supporter and quite a mentor, and I think it's through Lambert that he made a connection with the Ryrie family," she says.

"Gruner went to the Ryrie property and painted a couple of works, and I think that might have been the trigger for his travels through the region, though I'm not sure. He seems to have made connections through the Sydney clubs that the pastoralists were involved with, and then kind of got 'handed around'. He turns up on all kinds of properties, painting from the front door and so on.

''He loved the light. He loved the light of Canberra, because of its incredible clarity - on a clear day you could see forever."

While in Canberra, he stayed with various pastoralists, but also government officials and even a camping ground, possibly somewhere close to the Acton Peninsula, where, says Clark, he was apparently visited by the governor-general, among others.

"He also camped on the road - he didn't mind roughing it, at all … in sheds and sometimes very small farm holdings. He was pretty easy," she says.

But, unlike his fellow "Master of Light" Turner, who was known for being squat and scruffy, Gruner famously scrubbed up remarkably well, which was useful when attending vice-regal receptions.

"There are a couple of very funny stories about fellow artists running into Gruner dressed up with a potential patron and being slightly snubbed by him. I think he scrubbed up really well, as you would if you really need to make a living," she says.

And Gruner did make a good living from his works, eventually buying a house at Tamarama, but, while he sold all his paintings, his output throughout his lifetime was relatively small - around 600-plus works over a 30-year career.

Gruner had long struggled with depression and alcoholism, and died in 1939 at the age of just 57. A homosexual, he left no descendants, and Clark has not yet tracked down the descendants of any living relatives, nor those of his companion, Brian Cannell. Besides his house, he left an estate of around £1000, and a collection of around 30 paintings by various artists, including Margaret Preston, who had been an admirer.

He was, says Clark, an artist's artist, and a curator's artist. His works are still popular for gallery audiences, and his reputation as a master of landscapes has endured among art historians. But his name has faded in the 75 years since his death.

Clark believes that this is largely due to timing. He was painting between the wars, and while he had his admirers and his champions, World War II, which broke out shortly before his death, seems to have intervened, and ultimately made him "yesterday's man".

"I think it is about the war, and about what happened next in Australian landscape," she says.

"By the time the war is over, it's the 'angry penguins', it's [Sidney] Nolan, [Arthur] Boyd, [Albert] Tucker. And to a subsequent generation, they didn't see that he had actually become a kind of modernist. They looked at him as being part of the between the wars, a kind of old-school landscape artist, like all of those people whose names are rightly forgotten."

And while Gruner never belonged to a particular school, or could even be considered an "innovator", the bundle of influences he absorbed in his lifetime combined to produce works that are quintessential.

"You know those funny little books published in the 1930s that are beautiful Australia and include lots of colour reproductions … he's in there along with Robert Johnson and really tedious artists," she says.

"And even given the quality of those reproductions, he stands out. But he was thought of in those terms, and I suspect that's why he's been forgotten except by artists and curators."

And while he had his champions, they too were part of a generation that died off thanks to the war.

"He was hugely supported by the editor of Art in Australia, Sydney Ure Smith. Most unusually, and this is really worth noting, he was supported by a spectrum of people," Clark says. He also taught at Ashton's school and was beloved by his students. But by the time the war was over, the world had changed.

The exhibition at CMAG will have only 27 paintings in common with the 1983 Sydney exhibition, giving it a different perspective, and one with a Canberra focus.

And Clark hopes it will go some way to changing the public's perception of Gruner and his work. At the time of the interview, Morning Frost, regarded as a masterpiece of Gruner's Emu Plains series, is on its way to Canberra to be hung as part of the show, and the Art Gallery of NSW is already bracing for the complaints from visitors that will surely ensue once they find the work missing from its regular spot.

Elioth Gruner: The Texture of Light opens at Canberra Museum and Gallery on March 8 and runs until June 22.