Show Me The Green
…screen, that is.
Once the exclusive domain of high-end post houses, today, even high schools are using green screen technology to add a layer of creative possibility that’s not really available any other way (yes, okay there is also blue screen, but who’s shooting film anymore? <sniff>).
The two scenarios I notice quite often with first-time (and even second – fifth time) green screen productions is a tendency to assume the set-up is overly complex or that just throwing up a couple of lights will cut it.
The captivating cellphone photo above is from a recent shoot of a spokeswoman. It was in the tiniest studio I’ve ever been in and uses a minimum number of lights (two of the lights are out of frame, hanging from the grid, above). If it looks like a jumble, I’ll break it down in a loose order of importance. I say ‘loose’ because in this context, every single light is doing a specific job in a specific way and they all have to work together. But it’s good to have a plan to get started.
- Light the background. Do this first, as soon as you know what will be in frame, and make sure every other light source in the room is off. Use soft light. In this example, I’m using a pair of Kino Diva 400s with grid cloth. One is on the floor, behind the talent’s feet. The other is in a mirror position from above. The result is perfectly even, flat light across the background that doesn’t vary by more than 1/8 stop. Keep the light level low. This will do wonders to reduce spill.
- Add the back/edge light. In this case, the talent’s dark hair and dark suit make back lighting straightforward. The purpose of the back light is not to create separation from a dark background, as would be typical, but to force an edge of white light that will overpower any green from creeping in, making the subject easier to key later.
- Light the subject. Start with the key light, as always. Plan to have the talent far enough away from the background so that falloff from the key light won’t reach the background, spoiling the nice even light you’ve created. Because the talent’s skin is significantly lighter than her clothing, a double net was added to cut the light on her face while the brighter bottom half keeps detail in her blazer. The fill light wasn’t actually a light at all, but a soft silver reflector.
- Obie light. As a finishing touch, a Kino BarFly was added just above the camera to open up the subjects eyes and ensure a pleasing catchlight or sparkle.
Not a light per se, but equally important, drape anything green that isn’t in frame. You want to avoid any green light bouncing onto your subject or reflecting in clothing or jewelry.
That’s just a taste of what to look for, but should get you close for most simple set-ups. It’s worth noting that modern keying software is so good, small errors are not nearly as disastrous as they once were. Still, quality in = quality out.
What? You say I missed a light that’s visible in the photo? Good catch! There is indeed a small clip light under the BarFly, but it was used for the lo-fi teleprompter rig and not lighting anything in frame so I didn’t count it 
