So the Blue Mountains-based artist and new Doug Moran portrait prize winner wouldn't be drawn on questions about his peculiar pseudonym.

"It's something I don't like to put my finger on," what told reporters after being announced as the winner of Australia's richest art prize.

"It's not a word that came up out of nowhere, it actually ... yeah. I think it's okay for it to remain a mystery, there aren't enough mysteries in the world.

"People are telling us too many things about themselves."

what, a National Art School alumni and former southwest Sydney local who was an Archibald Prize finalist in 2017, beat almost 1000 contenders - whittled down to 30 finalists - to claim the $150,000 award.

He won with a life-sized technicolour portrait of The Go-Betweens guitarist Robert Forster, who he also painted for the Archibald and previously in 2005.

He said he drafted the portrait with Forster over a home-brewed coffee at his Katoomba studio before completing the work over 10 days earlier this year.

"It is intriguing because in a way it captures its subject through a lack of solid form ... the subject seems to hover on the surface," curator Kelly Gellatly, one-of-the-three Moran prize judges, said on Wednesday.

"In terms of portraiture, for us it seems to capture the subject like a technicolour apparition, neither in concrete shape nor in exact likeness.

"It's not just about capturing a likeness, but about pushing the medium."

what said he appreciated Ms Gellatly's critique, and planned to use the prize money for art material and to buy himself "time to think".

He admitted it was a life-changing sum of money.

"I'll have 30 tiny brushes on the go and I line up my palettes, so I've got all cadmiums and cobalts, really powerful colours," what said.

"But I think their description is good.

"He (Forster) is a very special person, a very important artist in Australia."

Australian Associated Press