Handle with care ... Francis Bacon's Seated figure is unpacked at the Art Gallery of NSW. (Copyright: The Estate Francis Bacon DACS/Licensed by Viscop.) Photo: Peter Rae

It’s a rare painting of a long lamented lost love, and its temporary home in Sydney is striking.

Among the first of more than 50 Francis Bacon canvases to be unpacked over the next 10 days for an exclusive Sydney restrospective at the Art Gallery of NSW to mark the 20th anniversary of the Irish figurative painter’s death, Seated figure from 1978 is particularly special.

Valued between $35 million and $40 million, and never seen in an exhibition before, the two-metre tall painting shows Bacon motifs such as an umbrella and cricket pads on the upper human figure.

But it's the foreground figure that will draw in Bacon buffs: in profile it is clearly George Dyer, Bacon's younger lover who committed suicide with a barbiturate overdose in 1971, just as Bacon's major exhibition opened at the Grand Palais in Paris.

The fact that Bacon kept painting his dead lover's profile again and again shows he never got over the loss.

Having spent almost four years making his case to more than 30 international and Australian institutions to loan the Bacon paintings at a cost of more than $2 million for flights, handling and insurance, curatorial director Anthony Bond was pleased to gain eight rare works from private collections.

Seated figure is one such work, with striking purple and orange tones, and yesterday found a suitable home for the life of the Bacon retrospective, which opens to the public on November 17 and runs until February 24.

"I was talked into having orange walls by the designer, which I've never done before," says Bond. "I always thought white was just fine. But this particular painting on that orange wall looks amazing; it actually works."

There's also a painting in the show of Bacon's later, younger lover, John Edwards, sitting in front of a void. "But the body belongs to George," notes Bond. "So he'd taken John's head and just pasted it onto the body of George, which I find quite sad, really.

"I don't suppose John minded much. I mean, John didn't really understand Bacon's paintings at all. Probably less so than George Dyer did.

"John once said he'd asked Bacon, 'Why do you paint me like I look like a monkey?' Quite a lot of the portraits in Bacon's works have a mask-like quality; even the self-portraits."

The retrospective, Francis Bacon Five Decades, brings together works from the 1940s through to the 1980s. It comprises almost 10 per cent of Bacon's known output.

It was a labour of love for Bond, although he admits there were a few dark times when he worried it wouldn't come together. "Early on, I thought maybe this is just not going to be possible at all," he says.

Bond admits there was a couple of desired paintings he failed to get, but refuses to "name and shame" the one or two museums that were less than collegiate.

"Of the ones we got, those from the Tate Britain were dead easy. I asked for five, and they gave them to me. I think they have a soft spot for Australia. [Director Nicholas Serota] did once say to me, 'Well, we always try to help the colonies'," Bond says, laughing.

Bond considers Bacon the top 20th-century figurative painter. "Nobody paints anything like Bacon," he says. "He walked a tight line between figuration and abstraction. The paint is phenomenal and you don't get it until you stand a couple of feet away. You realise how risky it is."