The tech behind: âOnce Upon A Timeâ
Once Upon A Time
The ABC hitshow, first airing in 2011, is about fairytale characters that get cursed from their home, The Enchanted Forest, to a small town in Maine. Storybrooke. It all starts with Prince Charming, played by Josh Dallas, on his white horse, riding through the Forest in search for his true love Snow White, whoâs played by Ginnifer Goodwin. He wakes her up with the famous True Lovesâ Kiss. This is known as the end of the Disney movie. But for these characters itâs just the beginning. Because the moment they get married, and are about to share a kiss, the ceremony gets interrupted by none other than Snow Whiteâs worst enemy. The Evil Queen, whoâs geniously played by Lana Parrilla. And she makes an awful threat, she vows to destroy their happiness, if it is the last thing she does. What she doesnât yet know then, is that Snow White will give birth to a baby on the night that she casts the curse. Or actually, she does, to make sure that Snow White will really lose everything once the Dark Curse washes over. However, she didnât expect that the, then, baby, would escape through an enchanted wardrobe. The baby, named Emma, shall be known as the Savior. The one destined to break the curse when sheâs twenty-eight. In Storybrooke, the infamous Queen is known as Regina Mills. The town mayor, with a ten-year-old son named Henry, after her father, whom she killed to cast the curse. However, Henry owns a storybook, and knows exactly whatâs wrong with the town. And so he sets up a mission in search of his birthmother. Bailbondswoman Emma Swan, played by Jennifer Morrison. On the night of her twenty-eighth birthday he sets out to Boston to find her, sure of it, that sheâs the Savior destined to save everyone thatâs under the curse. During Emmaâs time in Storybrooke, we also see flashes of the backstories of the Storybrooke characters. The Enchanted Forest is a medieval place with castles, knights, princes, princesses, kings and queens. And monsters, like werewolves and ogres. Now thereâs one question: how do they do it? making all those castles and ogres? The answer: Green (and blue) Screen. Is it really that easy? Yes it is, because the show owns a huge 360 degree green stage. And not just that, they have 3D sets. Letâs dive into the history and innovations of green screen, green stages and the 3D sets that the show owns.
What is Green Screen?
Another word for âGreen Screenâ is Chromakey. If you use green screen for your visual effects, itâs called chroma key compositing, or chroma keying. Chroma keying is a visual effects / post-production technique for compositing (layering) two images or video streams together based on color hues (chroma range). The technique has been used heavily in many fields to remove a background from the subject of a photo or video â particularly the newscasting, motion picture and videogame industries. A color range in the foreground footage is made transparent, allowing separately filmed background footage or a static image to be inserted into the scene. The chroma keying technique is commonly used in video production and post-production.
The History of Green and Blue Screen
Before green or blue screen existed producers used double exposure to introduce elements that didnât exist into a scene which werenât present in the initial exposure. This was done using black draping where a green screen would be used today. In the 1930s the blue screen method was developed at RKO Radio Pictures. At RKO, Linwood Dunn used an early version of the travelling matte to create "wipes" â where there were transitions like a windshield wiper in films such as Flying Down to Rio (1933). For decades, travelling matte shots had to be done "locked-down", so that neither the matted subject nor the background could shift their camera perspective at all. Later, computer-timed, motion-control cameras alleviated this problem, as both the foreground and background could be filmed with the same camera moves.Meteorologists on television often use a field monitor, to the side of the screen, to see where they are putting their hands against the background images. A newer technique is to project a faint image onto the screen.Some films make heavy use of chroma key to add backgrounds that are constructed entirely using computer-generated imagery (CGI). Performances from different takes can be composited together, which allows actors to be filmed separately and then placed together in the same scene. Chroma key allows performers to appear to be in any location without leaving the studio.Â
Green and Blue Screen in âOnce Upon A Timeâ
Earlier I mentioned that the show uses a 360-degree Green Stage, and owns 3D sets. Crafting up to 400 VFX shots for each episode of Once Upon a Time is no easy feat, especially when there are 22 episodes each season. But the effects company behind the work, Zoic Studios, has mastered the art of virtual sets and integrated pipeline tools to make those deliveries possible. Having realized the effects for several episodic television series filmed largely on greenscreen sets, Zoic is well-versed in the area of virtual sets. That culminated in the development of iPad app called ZEUS:Scout  to aid in the planning of shots and shooting on virtual set stages.Â
âHow it works,â explains Zoic visual effects supervisor Andrew Orloff, âis that in the pre-production process the art department put together a SketchUp file and a piece of concept art for each of the virtual sets that weâre going to use, and we build those for real-time 3D playback. We convert them through Unity to our ZEUS:Scout app.â âWe upload all of those into a protected FTP site for Once Upon a Time and they have their whole library in the Scout app,â adds Orloff. âSo when weâre in pre-production weâve got the ability now for the director to pull up any of the sets, move around the sets with the controllers that we have in the app, and also use the gyroscope in the iPad to do real-time tracking. If theyâre sitting on a chair and they start moving around, they can look around the set as though they were standing in one spot on it and moving a magical window around it. If youâre on a greenscreen we can do a realtime composite as well.âÂ
As Orloff notes, the Scout app is most helpful in pre-production, helping Zoic and crew members decide on orientation of the actors to camera and the location of objects in the scene. Then when the cameras start rolling, thatâs when Zoicâs implementation of a complete virtual set system ZEUS comes into play.
The virtual world
ZEUS, short for Zoic Environmental Unification System, is a combination previsualization and on-set realtime compositing that relies on Lightcraftâs Previzion tech for realtime camera tracking and keying. It allows for 3D sets to be âpiped inâ to the Once Upon a Time greenscreen stage, helping the actors and crew to get an idea of what the final shots will look like.
Above you see the original plate.
and this is the final shot.
The Future of Green Screen
Looking further into the future, we see a new camera coming up, introduced at NAB by Lytro. The Lytro Cinema, and this camera can, in fact fix the problem, which green screen was created for. The problem of separating foreground and background. How? The answer is simple:Â Lytroâs primary power is its ability to capture accurate per-pixel depth information. With depth-based separation, you can easily keep or discard areas in the frame according to their distance from the camera. This could mean, that green screen wonât be necessary anymore in the near future.Â
The Future of Once Upon A Timeâs Green Screen Stage
The 360-degree, 3D stage they use in Once Upon A Time wonât be gone anytime soon, I suspect, as the show is going into itâs 7th season and possibly itâs last. And the shots look fairly realistic, for as far the representation of Medieval times go. But who knows, maybe weâll see the change to something similar to Lytro if the show gets renewed for an 8th season by ABC next year. Besides, when the show started in October 2011, we werenât even close to something as Lytro, and so the Green Stage was fairly innovative back in 2011, in a show with so many VFX effects and CGI. Also, the iPad app thatâs used: ZEUS: Scout is fairly innovative, you can already see the stage and how itâs going to look while using your iPad. How innovative is that for 2011?