Focusing on History

Effects artists restore old film footage of atomic weapons tests for the film 13 Days

By Karen Moltenbrey

More than four decades ago, during the 13-day Cuban Missile Crisis, the world hovered on the brink of nuclear disaster as two world powers squared off, ready to flex their atomic muscles. This scenario-perhaps the closest we've ever come to a nuclear war-is chronicled in the reality-based feature film 13 Days. Demonstrating the high stakes of this nuclear face-off, the movie opens with dramatic film footage of actual atomic bomb test explosions by the US and the former Soviet Union during the 1950s. Explosion shots are also used in scenes throughout the film.

Making these old, scratched, flickering clips palatable for today's movie audiences required the digital wizardry of effects artists at VCE.COM, a Hollywood-based visual effects company. "It's archival footage, so it has dirt, scratches, and other blemishes that occurred over time or were present in the original negatives," says Kurt Wiley, the VCE visual effects artist who performed most of the film restoration. "In the shot of Castle Bravo, the biggest nuclear bomb ever exploded, we were dealing with huge pieces of flying dirt, flickers and flashes, odd color shifts...you name it."

For VCE, peering into our nuclear history is not a new experience. The company's founder/president, Peter Kuran, owns a collection of archival film footage he purchased over the years while producing various films and documentaries focused on atomic history. Kuran also serves as a consultant to the US Department of Defense on the topic of film restoration and preservation. "It's important to preserve this visual legacy and help remind people in the future what this time period was really like," he says. "From my previous work, I have a clue in terms of what material is out there."

Visual effects company VCE made old film footage new again by eliminating scratches, dirt, flickers, and color distortions so the restored images could be used in a newly released feature film. -- Images courtesy VCE.com.

In fact, all of the nuclear explosion clips used in 13 Days were pulled from Kuran's film library. Whenever possible, Wiley used original footage of various blasts, but for the most part, he had to work with images that had been transferred from film that no longer existed to a different media, perhaps two or three times, each resulting in a loss of image quality.

Even the images that had already been restored by Kuran for his documentaries needed further cleanup. "A lot of that work was done in 1995, when I had fewer tools to work with, and no budget," says Kuran. "The producers wanted our footage but needed the images in better shape for their film."

While piecing together old footage for a movie may sound like a straightforward endeavor, that was definitely not the case for this project, given the poor quality of the images. Many shots were taken using hand-held cameras, while others were filmed from airplanes flying close to the blasts without the aid of today's camera stabilization equipment. Compounding this problem was the violent bucking of the aircraft following the blast, which resulted in jerky images that bounce around on the screen. Then there were the general effects of age, such as shrinking, which added more jitter, and color fading on the film as well as the negative, causing blue shadows and yellow highlights on subsequent positive images, Kuran explains.

To digitally correct the imperfections, Wiley first had the original film scanned in 10-bit Cineon file format, so that the final files would be in the proper bandwidth for the production. However, for the restoration processes, he converted the film into 8-bit format, so it would be compatible with his software tools, namely Adobe Systems' After Effects and Boris FX's Continuum plug-ins. This was done using After Effects' Cineon converter.

Each explosion required several passes, since changing one part of the shot affected the other parts. For example, one explosion shot required major stabilization and dirt removal, yet Wiley wanted to keep the clouds vaporizing in the background intact. So he created one separate composition of the clouds, then began working on the bomb portion of the shot.

Because the image was so jerky, the artist was unable to use a single stabilization target, so he chose an initial target within the frame and tracked it as long as possible using After Effects or Pinnacle Systems/Puffin Designs' Commotion. When he could no longer track the target, he chose another, then another, until that portion of the shot was stabilized. In some instances, he averaged these "trackers" to create the best tracking.

"I used motion displacement in After Effects to make sure the bomb was where it was supposed to be," says Wiley. "Once we had a steady bomb, the boundary edges of the film were kicking around like mad. So one cleanup job inevitably led to another, such as extending boundary edges outward to avoid having them appear within the now-stabilized film frame."

To maximize the effect of the bomb blasts shown in 13 Days, digital artists used Adobe After Effects and various plug-ins to restore original camera shots of actual atomic explosions. The image above shows one such image before it was digitally restored i

In various frames, the speed of the image coming into and going out of a keyframe did not match. This resulted in discontinuous and distracting jumps in the footage, which Wiley fixed by editing keyframe velocity parameters in After Effects. He often recombined layers of footage, staggering them in time to cover dirt, flashes, and other anomalies.

To remove the scratches or large specs of dirt in the film, Wiley used Commotion cloning tools. "You have to be careful doing this-sometimes you'll actually introduce artifacts that are worse than the original scratch or dirt," cautions Wiley. "Often it took several processes, using a combination of After Effects and Commotion, to get rid of a single scratch."

Once the major stabilization and clean up was complete, Wiley used Continuum plug-ins and filters to remove the excessive film grain caused by the lower quality of yesteryear's film stock and by the extremely high-speed cameras used to shoot the actual footage. "There's a limit as to what we can do because today's film stocks are just so much sharper," notes Kuran. The filters also were used to correct the illumination problems resulting from the excessive light from the blast.

"We didn't want any dirt, scratches, or grain to distract the audience. People would be focused on that, and that's all they'd see," says Wiley. "Then they'd no longer get the full impact [of the imagery]."

Although digitally restoring the footage presented numerous challenges, the effects artists believe it was a far better alternative than substituting 3D computer-generated images. "We talked to the client about this, and they wanted the most realistic im ages possible," Wiley says. "And what's better than the footage of a real bomb exploding?" Moreover, using 3D particle systems to achieve the effects in 3D also would have been extremely time-consuming, he says, and rendering would have been prohibitively slow.

"We wanted people to be transfixed without necessarily thinking that they were watching old archival footage," says Kuran. "There is only so much you can do because it is, in fact, archival footage. But I think it makes the [intended] impact."

After Effects, Adobe Systems (www.adobe.com)
Continuum, Boris FX (www.borisfx.com)