It's always best to place your subjects far away from the green background to avoid as much of this spill as possible, although the brightness of the background may still bleed over onto smaller subjects with details in the video. This is especially important if you're shooting with standard-definition analog camera equipment that has interlaced even/odd fields to deal with. In compositing, blue spill is less offensive on hair and skin tones, especially in night shots or composites where t he scene includes a lot of cool-colored light.