VFX has so many subsets and smaller elements that come together to produce awe-inspiring on-screen magic that we sometimes fail to acknowledge these cogs in the wheel. Here’s looking at one such all-important aspect – Compositing.
In simple words, compositing is a process in making visual effects whereby visual elements from separate sources are combined into a single image, creating the illusion that all the different elements are a part of the same scene. Chroma key techniques and green screens are all used to shoot live action shots that are later composited to create a scene for a movie.
How does Chroma Keying work?
We’ve all seen pictures or footage of actors working in front of a completely blue or green backdrop and then seen what the final outcome is in a movie with the details filled in. Have you ever wondered why the sets are draped in blue or green instead of any other colour? Blue or green backdrops are used for shooting live action footage that is due to be composited as they are the colours believed to be the farthest away from human skin tones making it easy to fill in a background without blurring the main characters out of the screen.
The blue or green backdrop is entirely replaced by alternate background video or CGI. Naturally, it goes without saying that the characters avoid wearing clothing that matches the backdrop, unless of course, that part of the character is meant to be blurred out or dissolved into the screen. For example, a character playing a floating head may be dressed entirely in blue so that only the head is composited.
Speaking of floating heads, let’s take a journey back in time to when visual effects were still at a nascent stage and explore the history of compositing for films.
Georges Méliès and the Four Heads
Georges Méliès was a French director and illusionist who pioneered many techniques in filmmaking in the early 1900s. As an illusionist, it is no wonder that he was intrigued by what one could do with a camera and wanted to create magic using film as his medium. In 1898, he created a film Un homme de têtes (A man of heads) which featured on of the first known use of multiple exposures of the same object.
In the film, he removes his head and places it on a table next to him where it starts looking around. After doing this a couple of times (so there are three heads on tables next to him and one where it should be) he then plays a banjo with the three heads joining him in chorus. He used a technique known as substitution splicing to achieve this effect where he’d stop the camera every time he “took off” his head, placed a black bag over his real one while holding a dummy head in his hands. He used a black glass screen to create a matte leaving a portion of the film unexposed, which he would then shoot over to get the desired effect.
Pretty cool, we reckon!
Norman Dawn and Matte Painting
Another pioneer of the filmmaking world, Norman O. Dawn is credited as one of the early cinematographers to refine the technique of matte painting. He developed a technique that joined together a photograph and a painting to effectively “create” a location for the scene being shot. He would place his paintings and photographs on a large sheet of glass. Black tape was then placed over the parts of the camera where the painting would go, after which the live action footage was shot.
Frank Williams and Travelling Matte
Glass panes limited scenes as the camera needed to remain in one place. Frank Williams overcame this by developing the travelling matte method in 1918 where he placed actors in front of black backgrounds. The film would then be copied to create high contrast negatives of the actors which would be then superimposed on the required scenes without creating ghostly double-exposures.
The Dunning Process
Notably used in King Kong in 1933, the Dunning process was created by Carroll D. Dunning. This process used blue backgrounds while the foreground action (or actor) was illuminated using a strong yellow light. Unfortunately, this process became redundant with the advent of colour films.
Sodium-Vapour Lighting or Yellowscreen
This method was developed in the 1950s and relied on the narrowband characteristics of LPS lamp. Special black-and-white film can record this light. A special camera was used to record on two spools of film simultaneously. One spool recorded the actors (and other foreground objects) while the other was used as a mask for combination with a different background. Alfred Hitchcock famously used this method in his classic movie The Birds.
CGI along with advances made in blue and green screen technology made this method impractical, until eventually matte paintings became digital bringing us to today’s spectacular visuals on screen.
How’s that for enlightenment?
Got more questions about compositing? Ask one of the experts at Toolbox Studio!
At Toolbox Studio, we are armed with the tools and more importantly the people who work day in and day out to deliver high-quality compositing outputs for our clients across the globe. Learn why we are considered masters of VFX and browse through the several services that we provide under this umbrella.