Watching the solemn parade of special forces soldiers climb into their trucks, blessed by a priest, and drive into the grey Afghan night, Australian artist Ben Quilty wondered if they would ever return.

Quilty, winner of Australia's prestigious Archibald portrait prize, spent 24 days embedded with troops in Kandahar and Tarinkot as the nation's official war artist, sketching, photographing and filming life as a modern soldier.

It is an "often very mundane existence, spiked with these extremely horrific, terrifying moments all the time -- much more than we hear in the press, they're all engaged constantly," he told AFP.

"People say 'So tell me what it was like', and it's an impossible question to answer. (For the soldiers) after eight months of driving out there into the desert and being engaged by an enemy, being involved in deaths so directly, there's no answer."

The embed in 2011 led to a collection of works titled "After Afghanistan" that is currently touring Australia after being exhibited in Sydney's National Art School this month.

The portraits -- huge, thickly textured canvases of visceral flesh and dark tones -- show the human face behind the headlines about shootings, helicopter crashes and IED (improvised explosive device) strikes in Afghanistan.

Quilty said his journey to Afghanistan took him to the extremes of human experience, continuing his work's exploration of masculinity and what he described as its "self-indulgent" rites of passage.

He was invited on very short notice, given three days to accept the assignment and deployed six weeks later.

The pre-deployment training, which he described as "emotional preparation" for some of the worst possible outcomes, was in itself an inspiration.

"(It's) quite (a) confronting and very moving experience to sit in this big theatre in Sydney with all these quite often really young people who are listening to this stuff with very real reason -- they're going to Afghanistan."

Once deployed, Quilty said he tried to remain in the background, feeling out of place and way out of his depth as rockets sailed into Kandahar base at night and he lay "shit-scared" on a cot in an armoured shipping container.

The troops were intrigued by his presence, a welcome break from the monotony and adrenaline of their lives, and Quilty said he met "quiet, sensitive and normal" people.

The major question for Quilty, who shirks simplistic labels like "pacifist" or "anti-war" but was terrified as a young man about the prospect of conscription, was "why".

"They're 18 and they look like they can't even shave, (you want to ask) 'does your mum know what you're doing? What are you doing here?'".

Some were following the family tradition, others were attracted to the emphasis on fitness, physicality and hierarchy, or had flunked school and saw military service as more respected and better paid than learning a trade.

It was a sensitive topic -- they spoke freely about the sounds a wounded man made, about watching a comrade die or suffer horrific injuries, but the why was something they couldn't, or wouldn't explain.

"They've just got to get through this experience," he said.

"A lot of them wanted to get out, but they don't talk about that, there's no way they want their friends to hear that. It's destructive, you've got to keep your shit together for everyone."

The pressure can boil over -- once Quilty saw an all-in brawl break out over a hockey game in Kandahar and he was warned to stay away from the American quarters, where women walked around "wearing bra tops with M16s slung across their shoulders, the guys have tattoos and big chains and M16s and sidearms".

There were also profound moments: special forces soldiers doing a yoga class, farewelling a patrol with a priest's blessing of the trucks at 3:00 am.

"It's one of the most moving things I've seen, the men climb in very quiet, very concentrated, and drive off into the desert," he said.

"Every time you see someone drive through those gates you wonder if they're going to come back."

Once back in Australia Quilty said he found it difficult to reconnect with the experience and asked some of the men and women if they would come to his rural studio and sit for him. Bleak, stirring tales emerged.

"It was impossible to make a bad painting of those people. They're unbelievably powerful subjects, broken sometimes," he said.

Several of the men have been diagnosed with post traumatic stress disorder; Quilty spoke to their psychiatrists to ensure he was doing the right thing by asking them to relive the events that scarred them so deeply.

"All of them said yes, it's been a really positive thing in an otherwise bleak year for these guys," he said.

Quilty was surprised by how philosophical the troops were: "The literature they're reading in Afghanistan predominantly is about the strategies of withdrawing from war and how wars end successfully," he said.

There was a particular conversation in the mess one evening that stayed with him.

"One of them said 'War follows politics' and a much older man said 'No, you're wrong, politics follows war'," said Quilty.

"It's the extremity of human nature and there has to be participants, and they're it."