Problems using Blue Screen

  • This topic has 5 replies, 1 voice, and was last updated 10 years ago by AvatarAnonymous.
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    • #37745
      AvatarAnonymous
      Inactive

      Lately I have had a problem keying a person who is wearing black when standing agaisnt a blue-screen. Everything keys out nicely except small particles of the black on a subjects shirt. The shirt looks like swiss cheese with some of it looking appropriately blackand some of it becoming transparent and showing thrutothe bluescreen . Any suggestions on how I can fix this?

    • #167236
      Luis Oscar MaymiLuis Oscar Maymi
      Participant

      How are you lighting your subject and the blue screen? For chromakeying you need to light your subject and the blue screen as evenly as possible, if not small black particles will appear. It also depends on what software you are using to chromakey and the camcorder. A camcorder with one CCD or CMOS will never give you the results of a 3 CCD or CMOS camcorder. The basic three point lightning apply here, so the only solution is trial and error until you get close to a perfect result.

    • #167237

      Also make sure you have no lint on the black shirt. Black tends to show that a bit, and it might confuse the keying.

    • #167238
      Avatarcomposite1
      Member

      Yeah bluescreen is a bit trickier than green. If you are using After Effects CS3 or 4, you can use the Foundry’s ‘Keylight’ plug-in to get a clean key. You might want to recheck your original keyed video and it’s lighting setup as you may have multiple shades of blue from either not lighting your background evenly or having a wrinkled background. Hopefully your keying software will allow you to take multiple samples of blue from the scene. That should help some.

      Also prior to shooting when your talent wears black or white, you want to take a roll of masking tape and roll it out on your hand sticky side out. Use the sticky side to get any lint off your talent’s clothing before you start shooting. That will also cut down on stray particles that may make it difficult to key out.

    • #167239
      AvatarGrinner Hester
      Participant

      get em away from the screen so there is less bounce. Eye drop the back drop and don’t hesitate to use garbage masks as needed.

    • #167240
      AvatarD0n
      Participant

      assuming you lit your subject and background properly, and still having this problem…

      gel your lights on your subject to a warmer color balance.

      most black materials look blue when slightly over exposed and many black synthetic fabrics actually give off a lot of uv to violet reflections….

      so warm toned lights will help, as will a uv filter on the lens.

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