This article might be perceived as containing spoilers for Captain America: Civil War. If you haven’t seen the movie, you may not want to read on.

One of the most startling moments in Captain America: Civil War was when Tony Stark showed up on screen looking like Robert Downey Jr. from the mid-1980’s. The actor was fresh-faced and youthful in a pseudo-flashback in front of a crowd at M.I.T.

The young Stark was created by the digital artists at Lola VFX, who recently spoke with The Hollywood Reporter on how they created their magic. The company worked with Marvel previously when creating the young Michael Douglas for Ant-Man.

For the scene in Civil War, the process started during production with Downey performing the scene. “Instead of completely replacing the actor with a digital double, this method allowed us to retain the actor’s performance and nuances,” Trent Claus, visual effects supervisor at Lola VFX, tells The Hollywood Reporter. “Then we began to adjust the on-set footage of Tony Stark through digital compositing.”

That process is akin to using Photoshop on a still image. Says Claus: “It is a similar process to Photoshop that uses some similar tools, but unlike Photoshop which is done on a single image, we have 24 frames per second of footage.

“Every feature of the face and body needed to be addressed in some fashion,” he says of the work that went into creating the youthful Tony. “One thing that happens to all of us is that the skin of the face gradually lowers in certain areas, and needs to be ‘lifted’ back to where it was at the age in question. But other changes are incredibly subtle, such as increase in the way light reflects off the sheen of the skin, a reduction in the appearance of tiny blood vessels under the surface of some parts of the face, or more blood flow in the cheeks giving them that familiar youthful ‘glow.’ “

De-aging a character by a span of 25-30 years can affect skin texture and complexion and can involve characteristics such as bone structure or posture, Claus explains. “Additionally, when working with the appearance of a well-known actor such as Robert Downey Jr., there is the added pressure of living up to the youthful appearance that audiences remember,” he says. “In this case, we analyzed footage of Mr. Downey at the approximate age that we wanted to target, which was around the time of the film Less Than Zero [when Downey was in his early 20s].”

Of course, when de-aging an actor like Downey, someone that has a long career behind him, it’s hard enough as it is, but when you add in a continuous close-up? There are no room for errors, something the folks at Lola VFX noted.

“The shot was nearly 4,000 frames long, with Tony Stark turning from one side to the other multiple times, physically interacting with other actors, and the set itself, and moving closer to the camera for a very long, uninterrupted close-up.”

The digital artists went on to explain that these methods aren’t always used for creative reasons, but that some actors are touched up for beauty reasons. While those cases are steeped in confidentiality, it is similar to magazine touch-ups to remove blemishes and reduce the signs of aging. They have also been used in the unfortunate situations where a character passes away before a film is finished.

“That’s a whole other level of complexity,” Debevec explains. “It’s not a matter of digital makeup but actually re-creating a digital version of the person that is three-dimensional, animate-able and relight-able. [In these instances], if you can base it on facial scans, that’s the best thing to do.”

The folks at Lola VFX definitely did a good job with Downey, bringing into his mind to re-live the last moment he had with his parents. Although the flashback scene was teased shortly before the film’s release, even going into the movie knowing to expect it, I found myself surprised by just how well they’d done with the de-aging process in this film. As fantastic as the process was in Ant-Man for Douglas’ Hank Pym, the final results were nowhere near as precise and clear as they were in Civil War. Having used this process twice now, who knows how Marvel will utilize this technology next? Are there any other characters that you would like to see in a flashback scene? Sound off in the comments below!

Captain America: Civil War is in theaters now!

Source: The Hollywood Reporter