Director Peter Weir on capturing the mood for Picnic at Hanging Rock

One of the most memorable features of Peter Weir's Picnic at Hanging Rock film is the rock itself.

A volcanic outcrop brooding silently in Victoria's Mount Macedon Ranges, its ancient menace seems to vibrate off the screen and into the psyche of viewers.

Amplified by the musical composition of Bruce Smeaton, it almost tempts curious audiences to climb into its shadows and vanish — just like the girls do in the film. 

Weir told ABC Radio Adelaide's Deb Tribe he had been told stories by a local shop attendant about tourists who had taken pieces of Hanging Rock over the years as souvenirs.

"They later mailed them back, saying they'd got a bad feeling or thought they'd done something wrong and wanted to return their little chip of rock to its rightful place," Weir said.

"It does make you wonder. There's obviously been a tremendous volcanic upheaval of some kind in the distant past."

Less of a mystery, however, is the lengths Weir and his team went to in order to capture this powerful presence.

The result was a film so unsettling that many believed it was based on a true story.

Finding that 'golden light'

Adapted from a 1967 fictional novel by the late Joan Lindsay, the film about a group of school girls who disappear on an excursion to the site in 1900 has been restored into a 4K version for the 50th anniversary of its release.

"The actual picnic itself is at the base of the rock where we found a location with beautiful light," Weir said.

"The cinematographer, Russell Boyd, said to me, 'It's only got this golden light between 12 and 1 in the afternoon, otherwise you're not going to get it' because the trees were very dense.

"The scene would take about six or seven hours to shoot, so we made the decision we would only film there one hour each day, which was very complicated because we had to break the set up and move to other locations on the rock.

"So that was tough and tricky to move that big crew around all the time just for a one-hour shoot, but it gave that particular scene its look and glow and that was essential."

Boyd and Weir also studied paintings from the Heidelberg School of Australian Impressionism, such as those by Frederick McCubbin, to create a certain look for the film.

"Russell came up with a kind of system of gauze netting on the lens that would create something of that kind of impressionistic look," Weir said.

"In fact, he got gauze from the wedding department of David Jones in Sydney.

"He tells us the story of going in there and the lady saying, 'Yes, can I help you?'

"I think it was an odd meeting."

Working from a solid blueprint

Weir said he had "a couple years to think" about how he would adapt Lindsay's novel, "and how to make it work because it was essentially a mystery story, a whodunnit".

"But there was never going to be that, 'Oh, the butler did it' kind of ending, thankfully," Weir said.

"On the other hand, a lot of the audience would be sitting there waiting for the usual kind of revelation, the Sherlock Holmes ending where it's all explained.

He said the shoot, which benefited from good weather during the exterior scenes at Hanging Rock, was made smoother due to a well-developed screenplay by Cliff Green.

"So much thought had gone into it, I think the screenplay was in good shape," Weir said.

Panpipes provide finishing touch

Adding to the film's dreamlike finish was the sounds of panpipes by Romanian folk musician Gheorghe Zamfir.

"[Composer Bruce Smeaton] had done a wonderful job, the girls climbing the rock for example, but it was just missing something," Weir said.

"One of the co-producers, Jim McElroy, came into the cutting room and said, 'I heard this haunting music last night on a documentary.'"

They tracked Zamfir down and phoned him in Paris but "he was a bit puzzled by it all and said, 'Oh, I don't do that kind of thing anymore. You want my orchestra.'"

The team eventually had to buy the mechanical rights off an LP that Zamfir had produced earlier and, following the film's release, the Romanian was pleased to see that his music "took off".

"In fact he re-released it, I think, and then came on tour here to Australia," Weir said.

A 'scrupulous' digitisation

Fifty years after its release, and after being voted the best Australian movie of all time in a 1996 poll by the National Film and Sound Archive and the Victorian Centenary of Cinema Committee, Weir's masterpiece was this year re-released in cinemas.

He said its 4K digitisation had required "intense work" to retain the feeling and glow of the film's "original photochemical process".

"The first look Russell and I got, it was too clean and too European in the light," Weir said.

"It had lost the golden glow, so we sent them back to work on that.

"They'd been so scrupulous in trying to produce an immaculate digital version of the film, they told me they'd had trouble removing a lot of little black spots on the picnic scene — until they realised it wasn't dirt on the original film, it was blowflies.

Weir said the process became "excessive" but he considered the end result to be "really quite striking".

"It looks like it was shot last week, it's fresh and clean, and I think it's retained the feeling," he said.

"It will always be different to the film's quality, but I think it has a quality that's quite equal, and I enjoyed seeing that version."