In the dark ages before green screens, or blue screens, filmmakers had to rely on in-camera effects for their backgrounds. Often, this meant using matte paintings or static backdrops incapable of showing movement.

Other times, particularly when films called for motion backgrounds of things like clouds and sunsets, it meant using something called front screen projection.

What is Front Screen Projection?

Quite simply, front screen projection refers to the broadcast of live background footage behind the foreground action or actors. (Think replacing a rear curtain with a rear movie screen.) If you’ve ever stood in front of a projection screen to narrate a PowerPoint presentation, you were effectively using this technique.

The main benefit to this, prior to the development of the green screen, was that it allowed for dynamic, motion backgrounds. However, there are other benefits to front screen projection, making it a technique that’s still used today.

The Advantages of a Live Screen

When filming with a green screen, you’re relying on an actor’s imagination—and the crew’s imagination—to support the scene. Actors and actresses must effectively pretend there’s a dashing sunrise or daunting cliff in front of them. And, perhaps more importantly, they have to effectively guess at its boundaries.

Projecting a motion background live behind them, conversely, gives the set a much more organic role—with no guesswork or imagination required. What you see is what you get.

Another benefit of front projection screens over green screens has to do with set props and clothing. During the making of “Oblivion” (2013), director Joseph Kosinski was told he couldn’t use his glass set designs because they’d complicate the post-production. The color from the screens would spill onto the reflective glass windows and tables and create a nightmare to paint out digitally.

Instead, Kosinski kept the glass and built enormous projection screens—we’re talking 500 feet wide by four stories high—and a rig of more than twenty projectors. In the video below, you can see the (impressive) results straight out of camera:

To capture the motion backgrounds projected on these screens, Kosinski sent a three-camera crew to capture the clouds, sun, and stars from the viewpoint of a Hawaiian volcano. As an additive result, the footage also gave him far softer and more natural light than he could have hoped for via green screen.

A live motion background of a sunset, as far as the camera and lighting are concerned, is effectively no different than an actual sunset—particularly when it’s 500 feet wide and several stories tall.

“What that allowed us to do,” says Kosinski, “was to not only capture it in camera, but use the reflected light of that footage to actually light the sets and the actors.”

The result, in Kosinski’s case, is a quality of light that truly can’t be beat (or faked) by modern studio alternatives—plus a few hundred hours of post-production saved by not having to paint out green or blue reflections.

“I think the projection was doing 95 percent of the homework,” Kosinski said in an interview with Film and Digital Times, explaining that if a shot ever needed extra light, they’d just bounce it off the projection screen.

[Photo and Video: Universal]