Buzz
In a scene from Netflix's sitcom Master of None, Aziz Ansari’s clumsy actor character, Dev, stands before a massive green backdrop in a movie studio. A disinterested director of a cheesy sci-fi movie casually tells him, “Honestly, most of this is going to be done in post [production]. It’s pretty meaningless. We probably don’t even need you here. It’s mostly going to be CGI.”
This satire may have struck a nerve with actors working on Game of Thrones, Marvel films, or the many other projects, whether high-budget or low, that rely on the chroma key technique for visual effects and grand landscapes. Some actors find themselves spending hours in front of green screens, visualizing the alien armies, explosive fireballs, or towering castles that special effects teams will later digitally insert. “You kind of lose track of the story a bit,” Idris Elba said about his experience with the green screen on Thor, adding, “It’s like, ‘Wait, what is this again? Oh, right, Frost Giant. Got it.’”
Among all the colors in the spectrum, why is green the chosen one? What makes this particular shade ideal for creating an empty canvas for special effects to be added later?
The truth is, there’s no special reason. Chroma-keying involves isolating a particular color or brightness value in an image, making it transparent during post-production so that another image or video can be layered behind the removed color. While “green screen” and “chroma key” are often used interchangeably, any color can be used for this technique. Green is favored because it’s a shade that doesn’t resemble any natural skin tone or hair color, which means no part of the actor’s appearance will be mistakenly removed in the process.
If a green costume or object is necessary, a blue screen is often used instead. This posed a challenge for the 2002 Spider-Man film. The team had to rely on a blue screen for the Green Goblin’s effects shots, but blue was already a key color in the superhero’s costume. As a result, they switched to green screens for scenes featuring Spider-Man. To make sure both characters appeared together in the same shot, additional tricks and special effects were employed. Filmmakers of the Justice League movie, which will inevitably feature Superman and Green Lantern together, should take note of this technique.
Though it might sound complicated, Hollywood has been using chroma key since the 1940s in The Thief of Baghdad, and local news stations also rely on it to place a meteorologist in front of graphics for weather forecasts. This is why weathermen (and weatherwomen) have to be careful about what tie or dress they wear on air.
