WEEKS OF WORK GONE IN A BLINK OF THE EYE

Irvin Kershner begs you. Please don't blink. For six months he put up with just five hours of sleep a night -- "every single night," he says with emphasis, shaking his head in disbelief -- with the rest of his day filled with nonstop hectic work. Then there were the humidity- soaked temperatures of 100-plus degrees matched for discomfort only by the howling blizzards ripping through subzero days, freezing his cameras, caking his beard with ice, and, at times, weakening his determination with do-sane-men-really-do-these-things doubts.

Of course sane men don't. Only people from Hollywood engage in such bizarre activities and then only while they are making movies, which is what Mr. Kershner was doing.

The reason you shoudn't blink, he worries, is that "you will miss something. There is so much going on in that movie that even if you keep your eyes open, you'll only see a third of it." Which, actually, would suit mr. Kershner just fine.

After all, as director to "The Empire Strikes Back," he would just as soon have movie audiences coming back for each of the remaining two-thirds, propelling "Empire" one hyper-step beyond "Star-Wars," the biggest moneymaking movie ever made. All the same, save your blinks for the credits.

"The Empire Strikes Back" is, in a sense, the ultimate in moviemaking, or at least one aspect of it: the art of creating the appearance of reality from the lack of it. Most films function in more or less real-life situations and rely on real-life actors for believability.

Films like "Star Wars" and "Empire," however, snatch their scenes from the thin air of pure fantasy and depend on the wizardry of special effects men for believability. In the case of a movie such as "Empire," 80 to 90 percent of what the movie audience sees is, in one way or another, a special effect, and the moviemakers, such as Mr. Kershner, go to extraordinary lengths to achieve even the slightest effect. The behind-the-scenes efforts to create the 722 special effects in "Empire" range from bits of sheer technical magic to backbreaking, tedious work.

For example, one scene in "Empire" calls for a remarkable small green creature named Yoda to raise -- via "The Force," of course -- Luke Skawalker's spaceship out of total submergence in the murky swamps of Dagobah, an island clogged with strange jungles and creatures far less amiable than Yoda. Since "The Force" would stoop to nothing so lowly as lifting, Yoda performs this feat with no hands. In the movie, the whole sequence takes all of 6 seconds and possesses nowhere near the razzle-dazzle of a dogfight between spaceships.

On the set, the sequence took 10 hours, Mr. Kershner said in an interview. Skywalker's X-wing fighter was a life-size model, about 35 feet long. "We had to raise it out of the water [the Dagobah swamp was an actual set built in the studio, complete with a pool of water and 50-foot trees]. So that it stayed completely level the whole time, it had to come up smoothly, with no jerky movement whatever, and then it had to glide evely over the water and settle on the shore. The whole thing had to look effortless."

How Yoda and Mr. Kershner accomplished this hocus-pocus is not so much a matter of magic as hard work. It required a small army of technicians -- pulling on cables (specially painted to be invisible on film), pouring water into the ship so that it would gush out -- "and a lot of tedious care," said Mr. Kershner. It worked, and it worked in just one take. It is a tribute to Mr. Kershner's prowess as a director that the majority of scenes were shot in one or two takes.

"I really did not have any choice. I had six months to shoot the film, and several takes per scene would have taken me way over that as well as way over budget."

As it was, he said, the final tally for the movie will probably run to $25 million, compared with $10 million for "Star Wars" but more than $40 million for "Star Trek." While he wouldn't put an exact price on the special effects, he did hint that it was "several million" dollars. In all, "empire" was 14 months in the making.

As much as any of this movie's effects, the likeable little Yoda will leave viewers both enchanted and wondering. He is the Jedai master who trains Skywalker in the ways of "The Force" and Jedai warriorhood.

Yoda is small -- 24 inches high -- green, and slightly wrinkled and has long pointed ears and three fingers on each hand. He walks. He talks. He can wrinkle his brow, raise his eyebrows, contort his mouth, and roll his eyes with ease. So how does this Yoda work?

"He is not a pupper or a man in a suit," Says Gary Kurtz, the "Empire" producer. "Yoda is a mechanical creature, operated by four people. We tried Muppets and we tried a monkey in a suit, but none of them worked. We tried everything imaginable.

"He took 8 1/2 months to perfect. The eyes were the hardest part, making them move and retain that human sparkle quality." The four men operated Yoda from off camera with a group of wires, and sticks attached to his body.

Frank Oz, the Muppeteer reponsible for Miss Piggy and others in the Muppet clan, plays the character of Yoda, both directing his expression and movements and creating his voice. Indeed, Yoda|s only flaw is that his voice sounds similar to a Muppert's named Grover on the TV show "Sesame Street."

Lucasfilm, the production company that made both "Empire" and "Star Wars," not only manufactures its own special effects from its San Francisco studio but has a creature research department. Presumably, the department auditioned other creature ideas before giving Yoda the part.

Another of its products is the Tauntauns, dinosaurlike creatures that Luke and Hans Solo ride across the frozen wastes of the ice planet Hoth. They were built as life-size versions and are manipulated by a gaggle of cables and ropes from the rear.

"It was incredibly confusing," says Mr. Kershner. "We would have this mass of people tugging and pulling just off camera while the scene on camera was very quiet, with Luke sitting calmly on a Tauntaun that was only moving its head to one side."

Those frozen wastes are just that: Norway in the middle of a blizzard. The Hoth scenes were shot there, and Kirshner and company spent some time in Africa, as well. Most of the shooting was done at EMI Studios in England. "It was the only place I could find that had 10 sound stages we could use at the same time," says producer Kurtz.

At least three of the stages were shooting at the same time, all the time, says Mr. Kirshner. He would move from set to set, directing the essentials of each scene, and then move on to the next, leaving a host of assistants to round out the edges.

"We hired literally every available carpenter in England," he says, "and every available plasterer" for set building. "We still couldn't get enough people. Ten sound stages is a mammoth effort."

The real nitty-gritty of, "The Empire Strikes Back," though, emanated from San Francisco, headquarters for Lucasfilms and its den of special-effects magic, appropriately called Industrial Light and Magic (ILM). Richard Edlund holds rank as head sorcerer, with 60 full-time apprentices scurrying about .

They have brought a few shudders to the Screen Actors Guild.Their creations, especially the wildly popular duo, R2D2 and C3PO, and their special effects are the undisputed stars of the most successful movie ever made, and its soon-to-be runner-up.

At ILM the problem of making a spaceship zip through the air is no big deal. "We've done it so often that it has become second nature to us," Mr. Edlund said in an interview. Nonetheless, it puzzles the rest of us, so how does he do it?

Basically, about all the special effects are done with miniatures or animation, mostly miniatures. The spaceships are only inches long (with the exception of Hans Solo's Millennium Falcon and Luke Skywalker's X-wing fighter, which are life-size, but these are actual sets and not used for producing a special effect). But when an outside shot of Darth Vader's star destroyer flagship fills a 70-mm movie screen, who's to argue that it is really only three feet long? The detailing is incredible and holds up under even the longest of close-ups. The insides are lit with tiny lights on the ends of optic fibers.

Making those spaceships twist and turn through the air at something akin to the speed of sound is also not that difficult, Mr. Edlund says.

"Flying spaceships around is run-of-the-mill stuff. The ships are mounted to a device with a big turntable and a pylon attached to the turntable." A ship is fastened to the pylon, which is specially lit so that it won't show up on camera , and can be moved forward, banked right or left, and tilted forward or backward , and can make wonderfully long sweeping turns. A special camera that moves on seven axes of its own simplifies matters considerably. As the ship executes its moves in the studio, the camera grinds away slowly, much slower than normal. When the film runs at normal speed in the theater, X-wing, and Tie fighters just about burn the screen off the wall.

Spaceflight gets harder, though, when more than one ship enters the picture, as they do in several chase scenes.The camera has to film the tracking of first one ship, then that of the other. On top of that, the camera has to shoot the background, usually a matte painting or a miniature set. All the shots then have to be combined into one print.

For example, the most difficult shot of this kind; according to Mr. Edlund, involved the Millennium Falcon (good guy) fleeing through space and an asteroid field from three Tie fighters (bad guys). On top of lots of twisting and turning, one of the Tie fighters collides with an asteroid and blows up.

The first step for ILM was to shoot the background -- space with lots of stars. The camera was pointed at a matte painting of space and moved along the paths that the spaceships would take. (Matte painting is a Hollywood art unto itself, and when you see a set on TV or in the movies that looks too fantastic to have been built, it probably is a matte painting.)

That's one shot. For the next, the special-effects men shot the Millennium Falcon hooked up to the turntable device zipping and dodging about. Then they hooked up each of the three Tie fighters and shot them separately. Eight distinct shots, so far, four in front of the matte painting for all the spaceship flight paths and four of the spaceships in flight.

Then the asteroid whirling through space on a path that would cross one of the Tie fighters was filmed.Then the camera recorded the explosion where the two collided. Even the shadows had to be filmed separately. All in all, says Mr. Edlund, the scene required 18 shots combined into a single sequence in the final print.

Fortunately, the camera does much of its own work. Developed by John Dykstra , the special-effects master for "Star Wars," the Dykstraflex camera not only moves on multiple axes but comes with its own computer that plots and remembers all the various paths of the spaceships and asteroids. It moves along these paths by itself, without benefit of human touch. What else would you expect from "Star Wars"?

Dykstraflex ranks as the major technological development out of "Star Wars." Mr. Edlund thinks a special composite printer ILM developed will emerge as the most significant piece of movie mechanics from "Empire." Those multitudes of the special-effects camera shots have to come out as a single print somewhere, and the composite printer does that job.

What makes ILM's printer so special, though, is that it can combine so many shots without any visible evidence of doing so. It took a year and $500,000 to construct, which won't mean much to the people munching on popcorn, but "the industry has been waiting for something like this for years," mr. Edlund says.

In fact, the special effects are intended to be taken for granted.

"The whole purpose is to make the movie seem real, to give the audience the feeling that they are really there," he says. For that reason, the camera never seems to gawk at the effects, never indulges in long sweeping shots of the outside of a spaceship, and much of the equipment deliberately looks used. "We want to present a spaceship as though it were a car parked on the street. Just because it's the future doesn't mean things will always be new," says Mr. Edlund. Actually, for the record, "Empire" and "Star Wars" are not set in the future but "long, long ago in a galaxy far, far away."

"What you are doing," he says, "is taking reality apart and photographing it bit by bit and then putting it back together again."

He considers the special-effects piece de resistance to be the scene where, on the ice planet Hoth, the audience first sees giant, four-legged, walking, mechanical fighting machines stalking out of the horizon to pounce upon the rebels. Although the close-up shots of these armored monsters are accomplished with miniature versions, the distance shots are animated. Filmmakers have never been able to move such animated objects over a physical set without making it appear that the object floats. The technique requires animating the monster, shooting it, and then combining that shot with one of the landscapes the monster is supposed to be walking on.

In this case, the landscape was snow, and a successful scene required these fighting turtles -- as some have called them -- to make footprints as they approached the camera. Timing the animated feet coming down with the appearance of footsteps on a physical set proved to be an extraordinary task, Mr. Edlund says, and he credits Dennis Muren, director of effects photography, with pulling it off. The sequence where these giants come out of the horizon lasts only a few seconds, but audience believability during those brief moments was paramount. Another scene with the fighting turtles (whose laser guns were also animated) involved the foot of one of them stepping on Luke Skywalker's downed ship, with our hero barely escaping. In that case, the crew in London built a 50-foot "foot" to do the deed.

"The people we have here are one of a kind," says Mr. Edlund. The average age at ILM is somewhere under 30, and what they do with special effects is unrivaled in the film industry. Their skills, on the other hand, are probably marketable nowhere else. No matter.ILM has two more films in the works for "Star Wars" creator George Lucas -- "Dragon Slayer" and "Raiders of the Lost Ark" -- and next year they begin on still another "Star Wars" movie. There are nine chapters in the entire saga, and only two have been made, making Lucas an extremely wealthy person, a movie corporation by himself. "The Force," and the special effects that make it alive, will be with us for some time to come.