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The Keys to Shooting Greenscreen African American skin tones have even more of a reddish feel. Fulks points to one scene of a girl on rollerblades.“We had to pay a lot of attention to lighting the back- ground and foreground elements, so I could get good separation.That was my biggest challenge, making sure I got good clean keys off the skin.” There was actually one scene that wasn’t shot on red, but shot on white. It was a wide shot of a man and his RV. This is where shooting on white actually did make sense. “Most of the actors are static, except that one guy,” explains Fulks.“I ended up creating a difference matte, then rotoscoping him off the white and changing the background to blue. I then painted the white RV blue.” Starting clean H Fulks had his hands full. He ended up hav- ing to do 18 comps and three different 3D pages in a week.The spot spent four days in offline with creative editor Steve Persin (Griot Editorial, a division of Grace & Wild), which was critical to get an approved offline with so many comps and a tight deadline. Fulks used Flame for the VFX and performed the final finish in Smoke. Grace & Wild’s VFX arm, Division X, provided the spot’s rotations and ticket animations via Maya. While Fulks likes film, he prefers to work digitally because he feels it’s cleaner. “Low- grade film is great, but not as great as HD or copying a 4K file from a Red file coming out of Scratch. It’s just cleaner with less grain. It doesn’t mean I think it looks better, it just keys easier when you are shooting green.” He has yet to work with a DSLR on a shoot. OLLYWOOD — Stephan Fleet, creative director at Encore Visual Effects, observes that the use of visual effects for tel- evision has expanded beyond the traditional “effects show” — with VFX now used across a wide range of programming, includ- ing the ABC single-camera comedy The Middle, for which he’s cre- ated a number of visual effects. Where possible, Fleet tries to have visual effects elements — greenscreen shoots, plates — shot using the highest quality acqui- sition system possible, regardless of the equipment used for main unit cinematography.Although he admits that a number of shows have created impressive results shooting non-effects work using highly-compressed, lower-end formats, he warns producers that images must be robust if they’re going to hold up after significant digital augmentation.“I always push to shoot 10-bit, RGB, 4:4:4,” he says.“A lot of the time we can deal with a 4:2:2 format — which is half the color resolution — but anything down from there makes it difficult to achieve high-quality results.” Given that the overwhelming majority of TV work today is shot digitally, he notes,“It’s important to be aware that many digital cam- era sensors don’t ‘like’ tungsten light. If you have time on set, it’s much better to light the screen with daylight temperature units. Often, there isn’t time and we can use the technology we have at En- core to fix an imperfect key. But I try to get it right in the first place because if you have to fix it in post — especially if you fall into roto territory — it’s going to take more time and more money.” Tracking software has become very sophisticated, acknowl- edges Fleet.“That means it isn’t as necessary as it once was to put actual trackers on the screen.They can still be helpful in situa- tions where it’s hard to find something else in the frame to track to or in situations where a 3D track might be necessary.When I do use trackers, I use tape that is the same color as the screen — I know that sounds crazy but I’ll use green gaffer’s tape to make pluses or points on the screen.The tape reads different enough from the screen itself that our artists can track from it, but it’s similar enough in color that it’s simple to key.” Fleet says there is no absolute standard approach to every facet of a greenscreen shoot.“What I do works for me and for the peo- ple I do this for, but other people do things differently.That’s one reason it makes a lot of sense to have an on-set supervisor from the same company that will be doing the compositing and CG.” 24 Post • July 2010 THIS OR THAT Framestore (www.framestore.com) in London recently worked with blue, but it wasn’t a screen.They completed visual ef- fects on a Kia spot, This or That, out of David & Goliath, LA, that features 45 photorealistic rapping hamsters that had actors wearing hamster-proportioned suits and blue over their faces, arms and legs.The studio then added CG hamster appendages. In the spot, these “street” hamsters rap to Black Sheep’s 1991 “The Choice is Yours” track and are shown enjoying all that urban life has to offer.There are even a couple of up- town lady hamsters turning their nose down at the others.The three main hamsters rap for viewers, singing,“You can get with this [a Kia] or you can get with that [a toaster].” The spot was shot on location, not in a bluescreen studio.“Each character was shot with proportioned bluescreen hamster suits and clothing on top,” explains executive pro- ducer Tim Keene. “Where possible, clean plates [i.e. with no action] were shot, so that we could ‘key’ off the blue areas of the suits and restore the background for any areas overlapping where our CG was going on top. By having the hamster-proportioned suits you get some indication of the light direction and the approximate shape of the hamsters for framing. Additionally, we had specific tracking markers on the bluescreen suits so we could body track the orientation of the heads, hands and legs to apply our CG to it.” Diarmid Harrison-Murray, head of CG, says that in the end, having blue hoods, hands and legs wasn’t really a benefit.“Being on location, and therefore not able to fully control the lighting, meant that not much of it could really be pulled as a key, so we ended up having to hand roto this stuff out anyway! Probably in hindsight, we would www.postmagazine.com have been better off with a much more neu- tral color, not blue or green, as not only did we have to roto the suits off, but we had to also paint out any blue motion artifacts.” Framestore had to accomplish a lot in a short amount of time — over 50 shots in a matter of two to three weeks once they had the final renders. “Prior to the final stages, we of course had huge amounts of anima- tion to get approved,” reports Keene. “Late changes in animation and on the look of the hamsters are an occupational hazard.With this in mind, we tried to ensure that the compositing process was as efficient as pos- sible, which is one of the reasons for using the Nuke — for its capability to use the raw render data CG and it not getting com- pressed in anyway.” For the fur, Framestore developed a new set of fur grooming tools to work with Hou- dini’s native renderer, Mantra, rather than the previously-used RenderMan. Since the main characters have CG faces and are rapping to a song, making the ham- sters’ mouths move in naturalistic ways with the music was key.“That was quite a chal- lenge,” says Harrison-Murray, “because you’ve got two opposing forces: one is try- ing to maintain the naturalistic shapes ham- sters make, and the other is trying to mimic and match that of the human rap artists. It’s always a balance between not losing the hamster and yet giving a convincing singing performance that we recognize.To find that balance is not an exact science, so it’s a case of finding a happy medium.” This or That was shot on 35mm with some background “reportage” material shot on the Canon 5D, such as the skyscrapers. Keene likes the DSLRs and feels they are getting better and better.“They have fantastic resolution of imagery and ease of use.You do have to bear in mind some of the limitations, like tracking, for example. Rolling shutters, as used on the 5D and Red, cause an offset be- tween the top and bottom of the image when panning, which becomes problematic when we’re tracking the cameras in CG. There are plug-ins and tools we can try to use to correct that, but it’s best to be avoided.” Even though this Kia spot didn’t use screens, other jobs at Framestore do, and while Keene agrees that keying software has gotten better, if the piece isn’t shot correctly it will always be a challenge.“In extreme cases where it simply doesn’t work, you have to go back and hand roto the elements.Where we see our role, in particular, is getting involved at the early stages to avoid this. From advising what needs to be shot in front of green-/ bluescreen, to helping get the exposure and correct light balance.”