Chroma Key Green (or Blue Screen) Setup

Updated: 23 January 2013

Here are some studio settings that work great for an indoor portrait of a subject against a green screen or a blue screen:

  • A: two slave flashes or monolights set to 12 W·s (or no more than 15 W·s) for lighting up the green screen
    • make sure these are diffused light (here, i bounced them off umbrellas)
    • set them at 45° to the green screen for even lighting
    • the screen should be less bright than the subject
    • make sure these light sources are not falling on the subject
  • B: white reflector to fill shadows in subject
  • C: camera on tripod, in Manual mode
    • “shutter speed” set to 1/250 s, or slower if your monolights require it
    • aperture set to f/4.5 (the fabric/muslin of the green screen should be blurred)
    • ISO set to 50
  • D: master flash or monolight attached to camera via sync/PC cable; light energy set to 50 W·s
    • this light simulates the primary light source (e.g., the sun) of the photo you’re going to use for the background
    • you need to move this light source up/down and left/right to get the right location (for proper shadows and reflections on subject)
    • you also need to match the hardness/softness of this light by moving it closer/father from the subject and/or modifying the umbrella or other diffuser — in this case i shot through a translucent white umbrella

Other Points:

  • Green light will bounce off B into subject’s face; if you have 4 lights, then use a fill light instead of reflector at B to solve this problem; I don’t have 4 lights, so my solution is in post-processing: in FxHome PhotoKey, I set “Spill Suppression” to Extended
  • Take a shot of a gray card so you can adjust white balance later (i recommend shooting in RAW mode)
  • If your subject’s feet are going to be in the final photo, be sure the green screen fabric/muslin is draped forward underneath his/her feet
  • Check your photo after you take it; zoom in using the LCD panel and make sure:
    • subject is in clear focus
    • green screen is out of focus
    • histogram looks good (no lost highlights or shadows)
    • green is less bright than the subject
    • shadows/reflections on subject match the background photo you’re going to use
    • lighting is even (and diffuse) across the green screen
  • For post-production, I recommend the PhotoKey software, which you can find at fxhome.com; you may decide to use PhotoKey first and then PhotoShop later; Here are some things I’ve learned about PhotoKey:
    • Matte view is very useful—turn it on and remember that your goal is to get rid of grey areas;
    • If there is green reflecting onto subject’s skin (see note above), then change the Spill Suppression settings
    • If the edge is weird, play with the Edge Color slider;
    • If green in the subject’s clothing is being removed:
      1. If easy, just use a Mask to ignore the area with green;
      2. Otherwise, slide Hue Balance to minimize the problem.

3 thoughts on “Chroma Key Green (or Blue Screen) Setup

  1. Pingback: Chroma Key Green Screen – Jonas Lee Photography

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