What Is Compositing?

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Photo Source: “Sleeping Beauty” Courtesy Buena Vista Distribution

From the lush backgrounds of “Sleeping Beauty,” to the fight scenes in “Avengers: Infinity War,” video editors use compositing to seamlessly combine visual elements from multiple sources into a single image. Keep reading to learn more about this popular technique and ways to use it in your own film project.


What is compositing?

Compositing in filmMarbellaStudio/Shutterstock

Compositing is the process of taking several visual elements from different sources and combining them into a single video. The video effects (VFX) technique is usually used to imply that the elements are from the same scene. Compositing mostly takes place in postproduction, but it can also be done in-camera using mattes or LED screens during production.

Manual compositing techniques

Manual compositing example from 'Un Homme de Têtes'“Un Homme de Têtes” Courtesy of Star-Film

Compositing used to be a time-intensive labor of love. Manual compositing techniques include:

Multiple or double exposures

Film compositing was first used in film at the turn of the 20th century, when director Georges Méliès used multiple and double exposures in “Un Homme de Têtes” and “Le Voyage Dans la Lune.” A multiple exposure is produced when two or more film frame exposures are layered to create a single image. 

Similarly, a double exposure layers two images on the full film frame. In “Un Homme de Têtes,” Méliès splices a scene in which he removes his head and places it on a table, multiple times, then plays music with the heads. To achieve the full effect, he made a rudimentary matte, or a background image that indicates which parts should be visible and which parts should allow other images to show through. Méliès used a black glass screen so that part of the film would be left unexposed, and then shot over that. George Albert Smith and Edwin S. Porter also used double exposure to create composite images in their films. 


Following in Méliès’ footsteps, filmmakers including Norman Dawn, Frank Williams, and Auguste and Louis Lumière used other forms of mattes to create composite images. Mattes allow filmmakers to layer live-action footage and negatives with photographs to create the appearance that actors are at different locations. 

Background projection

This technique projects a scene’s background onto plates to make it seem as though the two scenes are one. Think of an older film with a driving scene in which the background doesn’t quite seem to match—that’s background projection.

Manual chroma key

Other traveling mattes and wipes can be used to chroma key videos, a process that entails layering two videos together based on their hue. The process of manual chroma key compositing was refined by Petro Vlahos and Zbigniew Rybczyński, who implemented the use of green screens and optical printers. By 1980, Richard Edlund had created a Quad Optical Printer that expedited the chroma key compositing process.


Different types of VFX compositing

Compositing greenscreen on the set of 'Blade Runner 2049'“Blade Runner 2049” Courtesy Warner Bros. Pictures

Today, compositing is easier than ever due to the power of technology. Digital compositing techniques include:

Green screen

The green screen technique uses chroma keying to remove color from an image and replace it with something else. When compositing with a green screen, the green is removed and replaced with the desired background. 

This technique can also be used to depict real subjects in a fantastical universe, such as in “Alice in Wonderland”:


Max Fleischer founded the 3D animation compositing technique when he started projecting photos of live-action movie shots onto glass panels using a rotoscope, and then traced over the image. Today, rotoscoping is done with computers to create highly detailed, accurate composite images. 

The animated show “Undone” uses hyperrealistic rotoscoping. Director Hisko Hulsing told Backstage how this VFX compositing technique was used to depict the liminal space between reality and dreams. “The script [might say] something like, ‘the room falls into itself’ and then it was up to me and my team to come up with a visual representation of that,” Hulsing said. “We used [oil] paintings and projected them onto the 3D so the animation looks like it’s painted. It wasn’t so much me as a director but more as [the] production designer to make sure everything had the same look and then we had a team of compositors who brought all the layers together—line animation, colors, shading—to make it look [like] one cohesive world.”

Photoshop and analogues

Video editing software such as Photoshop allows editors to create composite videos by layering or painting on top of film frames.

Why use compositing?

Video compositing outcome in 'Black Widow'“Black Widow” Courtesy Marvel Studios

Compositing is used to create the illusion of a cohesive image that extends past the actual image reality. It can be used to:

  • Create multiple depictions of a single actor in one scene, such as in “The Parent Trap”:

  • Place different backgrounds behind a character, such as in “Aquaman”:

  • Add a new element into an already-existing image, such as in “Jurassic World”:

No matter what it’s used to depict, compositing allows multiple visual worlds to merge into one.

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