When filming a greenscreen project, is your talent—however professional they may be—looking a little green? Color spill may be the culprit. If you use a greenscreen, it can be hard to get a good key when your backdrop’s color starts reflecting on your subjects, making things look fuzzy and fake during postproduction. Basically, the green “spills” onto your subject, reflecting off their skin, through their hair (if they have light-colored hair), or any other place the green background bounces off due to badly placed lighting. Not to fear! There are quick fixes you can make to prevent the walls and floors from tinting your talent. Here are several ways summarizing how to reduce spill in your greenscreen setup.
Light It up! (But Not Too Brightly)
Most color spill can be taken care of in the initial stages of the shoot. Set up lighting so the greenscreen background is evenly lit, allowing for no shadows or hotspots where the light is particularly intense. These can interfere with getting a good key and may or may not be fixable in postproduction. (Wouldn’t you handle it now rather than later?) Experiment with lower wattages and placement of the lights to lessen saturation of the screen. If you have enough room, place a light behind your subject as well to remove the potential green halo effect later.
Location, Location, Location
Keep some distance between your subject and the greenscreen backdrop for several reasons. First off, it keeps your talent from casting shadows behind them, which can interfere with the key. Standard practice is to have them stand about six to 10 feet away. Again, make sure their lighting is in sync with the backdrop by stationing lights off-camera, and on either side, at 45-degree angles and slightly raised above your subject. While this prevents green from reflecting off the backdrop, consider whether there’s a chance of reflection below them as well. While chroma key flooring can provide a terrific and seamless effect in the background, subjects should not be standing on a piece of greenscreen fabric or painted floor. Stand or position them on a nonreflective, dark surface to prevent green undertones. Consider doing the same for the ceiling or any shiny walls. Paint or drape them with nonreflective black paint, paper, or fabric.
When deciding how to reduce spill in your greenscreen set up, go small or go home. Some photography and film experts advise reducing the area covered by the greenscreen, adding chroma key green to the walls, ceiling, and flooring. You don’t need to fill an entire room with green to get great shots. Scale back by covering a smaller area, then zooming in and cropping the shot. You’ll get just as good an effect, and the possibilities of reflection and color spill are greatly reduced.