How to melt a Wicked Witch? An elevator and dry ice. Courtesy photo

They had no computers. No green screens. No Industrial Light and Magic.

So how did filmmakers create the snarling tornado and other wonders in “The Wizard of Oz”?

Seventy-five years ago, special effects had to be truly special. If you wanted visual sorcery that left audiences spellbound, it took a movie MacGyver to make some magic.

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And for “The Wizard of Oz,” that magician was A. Arnold “Buddy” Gillespie.

From 1936 to 1962 Gillespie served as the head of special effects at Metro-Goldwyn-Mayer on more than 180 feature films, including “Ben-Hur,” “Thirty Seconds Over Tokyo” and “Forbidden Planet.” He was nominated for 12 Academy Awards and won four.

We asked John Fricke, a New York City “Oz” historian and author, how Gillespie did it.

The twister

The special effects experts couldn’t just take a camera out to Kansas and wait for a tornado. They had to make one.

“They tried a test first with a water vortex, and talked about rubber, and finally settled on cloth,” Fricke said. “They came up with a 35-foot-long muslin stocking that they wrapped around chicken wire to give it a conical appearance.”

Gillespie rigged up a gantry crane, rotated by a motor, that traveled the length of the soundstage. The base of the tornado was fastened to a car below the stage, where the crew moved it along a track.

The farmhouse, fence, barn and prairie all were done in miniature, and clouds were painted on glass. Wind machines and dust added the final touch. They filmed the tornado sweeping across the prairie from several angles, at distances, coming close to the camera and going away, Fricke said.

“Once the (tornado) film was complete, they showed it as rear projection behind the actors,” he said.

How realistic was it?

“The Weather Channel did the one hundred most memorable moments in weather history,” Fricke said. “Number fifty-something was the tornado in ‘The Wizard of Oz.’ Several meteorologists said it was that depiction of a tornado that made them want to pursue careers in meteorology.”

The winged monkeys

In one of the most frightening scenes in the movie, the Wicked Witch of the West (Margaret Hamilton) sends her army of flying monkeys to abduct Dorothy (Judy Garland) and attack her friends. Gillespie considered animating the scene but scrapped the idea after realizing it wouldn’t look right.

“So they employed about a dozen diminutive men,” Fricke said. “Some were jockeys, and they used a couple of little people who played Munchkins. They put them in costumes and hung them by very thin piano wire from the sound stage, like live marionettes. Battery packs on their back caused their wings to flap.”

Gillespie used rubber miniatures to add scores of other flying monkeys to the scene.

The melting Witch

Dorothy throws a bucket of water on the Wicked Witch of the West, “liquidating her,” as the Wizard later explained.

“It was the most basic thing in the world,” Fricke said. “They put Margaret Hamilton on a small elevator platform that dropped below the soundstage. They tacked the hem of her witch’s dress around the outside of the elevator so it would stay up. Then the air rushing up the elevator shaft puffed up her skirt.

“Also under the skirt they put dry ice for the steam effect. And then the finishing touch was they put a bigger witch’s hat on her head when she was melting so it would look like her face was smaller.”

Hey, who needs computers?

This story was originally published August 15, 2014 6:11 PM.