In the 1980 movie "The Empire Strikes Back," Luke Skywalker, lost and confused on the desolate planet Hoth, is blasted by a frigid blizzard.
Well, not exactly.
While some of the footage was shot in snowy Norway, cast members spent much of their time in a toasty studio in London. The nasty weather on planet Hoth was actually a miniature studio model sprinkled with baking soda. Massive fans created the blizzard. And the crunching "snow" under the actors' feet? Salt.
When George Clooney's boat is tossed like a bathtub toy in this summer's "The Perfect Storm," the weather you see isn't nature's doing. Hollywood special-effects artists are masters of illusion when it comes to fake rain, wind, and snow.
Moviemakers began using special effects in the late 1800s. Their "weather" was anything but natural.
For snow, chopped-up chicken feathers were blown over the actors. But when the feathers started going up actors' noses, directors switched to pulverized potato chips.
Prior to "It's a Wonderful Life" (1946), the famous Christmas film, white-painted cornflakes were used for snow. They fell with a clatter and crunched so loudly when walked on that sound couldn't be recorded. Actors' lines had to be dubbed in later.
Special-effects coordinators for "It's a Wonderful Life" needed quieter snow. They sprayed the streets of "Bedford Falls" with 3,000 tons of shaved ice, 300 tons of gypsum, and 300 tons of white plaster. Some 6,000 gallons of soap-foam "snow" was also used. Silent-falling Foamite - made from the chemicals used in fire extinguishers - simulated falling snow. (Note: It was 90 degrees F. when the snowy scenes were shot in southern California.)
Today's moviemakers use several methods to trick you into thinking it's real snow. Potato flakes (dehydrated flecks of potato), cotton batting (to make backgrounds look snowy), and a soapy foam that airports use to fireproof runways may be used. Potato flakes are preferred for snowfalls because the flakes are biodegradable.
'Blizzards' of packing peanuts
But directors must be especially careful. In close-up shots, observant viewers can tell when shaved ice is being used. Filmmakers must constantly reapply it to make it look real. To make blizzards, fan-blown particles of polyethylene are used. (What's that, you ask? Shredded packing peanuts.)
"Hurricane fans" up to six feet tall can generate winds of up to 80 miles per hour - and lots of noise. Fans with wooden blades are much quieter - especially compared with the early method of creating lots of wind on cue: airplane propellers.
In "Hurricane" (1937), 12 fire hoses gushed water at airplane propellers mounted on towers. It made filmgoers gasp. Hollywood scrambled to create even more realistic (but strange) weather effects.
Famous actor and dancer Gene Kelly sang his way through a simulated rain shower in "Singin' in the Rain" (1952). But since natural raindrops don't show up well on film, the special-effects producers reportedly mixed milk with the water used to make the rain. (Incidentally, filming in the rain seriously shrank the woolen suit Mr. Kelly wore.)
To make simulated rain look realistic, devices called "rainbars" are used. These are long two-inch pipes fitted with custom-made nozzles. The pipes are mounted high above the set. Water is pumped through hoses from a tank truck. Nozzles range from the Whirlybird, which soaks entire streets, to a "birds mouth" that sprays water in a 260-degree arc (so the camera won't get wet). Falling rain makes a lot of noise, so sometimes "rain mats" are used. The rubberized upholstery padding softens the sound of the drops hitting the ground.
Cranes hoist the rainbars at least 30 feet up. That way, the drops fall straight and hit the ground with the same velocity as real rain. Another key: lighting. Unless rain is lit from the back, you'll never see it on film.
A spectacular rain scene is in this year's "U-571," which was filmed in and around the Mediterranean island of Malta last year. The rain towers constructed are thought to be the biggest ones ever used. Some 15,000 gallons of seawater were pumped through the towers - and onto the actors - every minute.
Seawater, you can imagine, is very cold. But there wasn't enough fresh water to use. Sometimes, actors insist that only warmed-up water fall on them in rainy scenes. (Problem: Warm water tends to make actors' clothing steam.)
But Hollywood's weather champion is this summer's "The Perfect Storm." Computer-generated images were used, of course. But many of the mechanical effects were filmed in a huge, 90-ft.-square water tank that was about 25 feet deep.
Full-size boat, pint-size ocean
A computer-controlled gimbal rocked the 69-foot-long replica of the fishing boat Andrea Gail. Six water cannons, plus wind machines, rain machines, and wave machines soaked the boat and crew. But while many moviegoers agree it looks authentic, there's no comparing it to the real thing.
Sonny Layton, captain of the Lady Grace, the boat used as the replica of the Andrea Gail, has been in two hurricanes.
"It's the wildest ride," he says. "You just can't imagine. You're just climbing up big mountains of water. I've had waves crash over the top of the whole boat."
Still, most of the water in "The Perfect Storm" could never make you wet. Why? Because it's all digital - computer-generated water. "Blue screen" technology lets filmmakers put in the background later.
Helen Elswit is a visual-effects expert who worked with Industrial Light and Magic (ILM) in San Rafael, Calif. ILM provided computer-generated imagery (called CGI) for "Storm." Computer-generated images of water were blended with images of real water to create those mammoth - but fake - waves.
John Anderson helped producers understand how giant waves are formed. He's a former professor of atmospheric and oceanic sciences. He helped filmmakers construct computer models of waves. Next, digital "particles" were scattered across the waves to create the illusion of whitecaps. Computer generated "fuzz" was added for sea mist and flying foam.
Virtual weather effects, while difficult to achieve, are more easily controlled than actual effects. Take fog, for example. If you spray it outside using a fog machine, even a slight breeze can whisk it away. Hollywood fog is made from a glycerin mixture hooked up to a fog machine. Or it may be created using a chunk of dry ice in a different machine. Bee smokers (used to calm honeybees) are sometimes the best way to create well-positioned fog.
Geoff Dann is with High Output, a Boston-based special-effects rental company. He sums up atmospheric effects this way: "That's the movies for you: It's not real unless it's fake."
(c) Copyright 2000. The Christian Science Publishing Society